FR3064629A1 - PROCESS FOR PRODUCING AND PURIFYING 2,3,3,3-TETRAFLUORO-1-PROPENE - Google Patents

Abstract

The present invention relates to a process for purifying 2,3,3,3-tetrafluoro-1-propene (1234yf) from a first composition comprising 2,3,3,3-tetrafluoro-1-propene, 1, 1,1,2,2-pentafluoropropane (245cb) and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E), said process comprising the steps of (a) contacting said first composition with at least one organic extractant to form a second composition; (b) extractively distilling said second composition to form a third composition comprising said organic extractant and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E); and a stream comprising 2,3,3,3-tetrafluoro-1-propene and 1,1,1,2,2-pentafluoropropane (245cb), (c) recovering and separating said third composition to form a stream comprising said organic extractant and a stream comprising trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E). The invention also relates to a process for producing 2,3,3,3-tetrafluoro-1-propene.

Description

Technical field of the invention

The invention relates to a process for the purification of 2,3,3,3-tetrafluoro-1-propene. In addition, the invention also relates to a process for producing and purifying the

2,3,3,3-tetrafluoro-1-propene.

Technological background of the invention

Hydrofluorocarbons (HFCs) and in particular hydrofluoroolefins (HFOs), such as 2,3,3,3-tetrafluoro-l-propene (HFO-1234yf) are compounds known for their properties of coolants and heat-transfer and extinguishing fluids, propellants, foaming agents, blowing agents, gaseous dielectrics, polymerization medium or monomer, support fluids, agents for abrasives, drying agents and fluids for power generation unit. HFOs have been identified as desirable alternatives to HCFCs due to their low values of ODP (Ozone Depletion Potential or ozone depletion potential) and GWP (Global Warming Potential).

Most hydrofluoroolefin manufacturing processes use a fluorination and / or dehydrohalogenation reaction. This type of reaction is carried out in the gas phase and generates impurities which must therefore be removed to obtain the desired compound in a degree of purity sufficient for the intended applications.

For example, in the production of 2,3,3,3-tetrafluoro-l-propene (HFO1234yf), the presence of impurities such as trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) is observed. Secondary products such as, for example, 1,1,1,2,2-pentafluoropropene are also formed. The purification of this type of reaction mixture can be carried out for example by distillation. However, when the compounds to be purified have boiling points too close or when these form azeotropic or quasi-azeotropic compositions, distillation is not an effective process. Extractive distillation processes have thus been described.

WO 03/068716 discloses a process for recovering pentafluoroethane from a mixture comprising pentafluoroethane and chloropentafluoroethane by distillation in the presence of hexafluoropropene.

WO 98/19982 also discloses a process for the purification of 1,1-difluoroethane by extractive distillation. The process involves contacting an extractant with a mixture of 1,1-difluoroethane and vinyl chloride. The extraction agent is chosen from hydrocarbons, alcohols, chlorocarbons having a boiling point between 10 ° C and 120 ° C. As mentioned by WO 98/19982, the selection of the extraction agent can prove to be complex depending on the products to be separated.

Summary of the invention

The present invention allows the purification of 2,3,3,3-tetrafluoro-1-propene. The present invention makes it possible in particular to obtain a current comprising 2,3,3,3tetrafluoro-1-propene and 1,1,1,2,2-pentafluoropropane having a low content of trans1.3.3.3- tetrafluoro-l-propene (1234ze-E). The present invention thus allows the production of

2.3.3.3- tetrafluoro-l-propene with improved purity.

According to a first aspect, the present invention provides a method of purifying the

2.3.3.3- tetrafluoro-l-propene (1234yf) from a first composition comprising

2.3.3.3- tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb) and trans-1,3,3,3tetrafluoro-l-propene (1234ze-E), said method comprising the steps of :

a) bringing said first composition into contact with at least one organic extracting agent to form a second composition;

b) extractive distillation of said second composition to form:

i) a third composition comprising said organic extractant and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E); and ii) a current comprising 2,3,3,3-tetrafluoro-1-propene (1234yf) and the

1,1,1,2,2-pentafluoropropane (245cb),

c) recovering and separating said third composition to form a stream comprising said organic extractant and a stream comprising trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E); preferably the stream comprising said organic extractant is recycled to step a);

characterized in that the first composition is obtained from a mixture C comprising

2,3,3,3-tetrafluoro-1-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans-1,3,3,3-tetrafluoro1-propene (1234ze-E) and HF, said mixture being subjected to the following stages:

i ') bringing said mixture C into contact with an aqueous solution of hydrofluoric acid of concentration greater than 40% by weight to form a two-phase current comprising

2.3.3.3- tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans-1,3,3,3-tetrafluoro1-propene (1234ze-E) and HF, ii ') storage of said second two-phase current in a buffer tank, said two-phase current consisting of a liquid phase and a gas phase, iii ') passage of said gaseous phase from said second two-phase current in an absorption column fed against the current by an aqueous stream to form a current Cl comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans1.3.3.3- tetrafluoro-l-propene ( 1234ze-E) and a current C2 including HF.

According to a preferred embodiment, the method also comprises the steps of: iv ') neutralization of said stream C1 obtained in step iii') with an alkaline aqueous solution to form a neutralized stream C3, and v ') drying of said neutralized stream C3 obtained in step iv ') on a molecular sieve to form a neutralized and dried stream C4 comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2pentafluoropropane (245cb), trans- 1, 3,3,3-tetrafluoro-1-propene (1234ze-E).

According to a preferred embodiment, the aqueous hydrofluoric acid solution used in step i ') is at a temperature between 0 to 30 ° C before being brought into contact with said mixture C.

According to a preferred embodiment, the liquid phase resulting from the mixture of said liquid phase of said second two-phase stream and of said stream C2 is distilled to form a stream D, preferably at the head of the distillation column, comprising hydrofluoric acid containing less of 500 ppm of water and a stream E, preferably at the bottom of the distillation column, comprising hydrofluoric acid in the form of an aqueous solution of concentration less than 50% by weight.

According to a preferred embodiment, the ratio between the flow rate of the aqueous stream supplying the absorption column in step iii ′) and the quantity of hydrofluoric acid in said mixture C expressed in kg / h is between 0.05 and 1.22, preferably between 0.33 and 0.54.

According to a preferred embodiment, the method also comprises a step of recovering said stream ii) comprising 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2pentafluoropropane (245cb) obtained at step b), and of distillation thereof to form a stream A comprising 2,3,3,3-tetrafluoro-1-propene and a stream B comprising 1,1,1,2,2pentafluoropropane (245cb).

According to a preferred embodiment, said first composition also comprises at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3,3pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf ).

According to a preferred embodiment, said organic extraction agent has a separation factor Si, 2 greater than or equal to 1.1, said separation factor being calculated by the formula

If, 2 = (yi, s * Pl) / (y2, s * P2) in which

71, s represents the activity coefficient of 2,3,3,3-tetrafluoro-1-propene in said organic extraction agent with infinite dilution,

Pl represents the saturated vapor pressure of 2,3,3,3-tetrafluoro-l-propene,

72, s represents the activity coefficient of trans-l, 3,3,3-tetrafluoro-l-propene (1234zeE) in said organic extraction agent with infinite dilution,

P2 represents the saturated vapor pressure of trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E);

advantageously, the separation factor is greater than or equal to 1.2, preferably greater than or equal to 1.4, more preferably greater than or equal to 1.6, in particular greater than or equal to 1.8, more particularly greater than or equal at 2.0.

According to a preferred embodiment, said organic extraction agent has a separation factor Si, 2 greater than or equal to 1.1, said separation factor being calculated by the formula

If, 2 = (yi, s * Pl) / (y2, s * P2) in which

71, s represents the activity coefficient of 1,1,1,2,2-pentafluoropropane (245cb) in said organic extraction agent with infinite dilution,

Pl represents the saturated vapor pressure of 1,1,1,2,2-pentafluoropropane (245cb),

72, s represents the activity coefficient of trans-l, 3,3,3-tetrafluoro-l-propene (1234zeE) in said organic extraction agent with infinite dilution,

P2 represents the saturated vapor pressure of trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E); advantageously, the separation factor is greater than or equal to 1.2, preferably greater than or equal to 1.4, more preferably greater than or equal to 1.6, in particular greater than or equal to 1.8, more particularly greater than or equal at 2.0.

According to a preferred embodiment, said organic extraction agent has an absorption capacity C2, s greater than or equal to 0.20, said absorption capacity being calculated by the formula C2, s = 1 / (72, s ) in which 72, s represents the activity coefficient of said at least one of the compounds consisting of trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extraction agent with infinite dilution , preferably 72, s represents the activity coefficient of said at least one of the compounds consisting of trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E), in said organic diluting extractor infinite; advantageously, the absorption capacity C2, s is greater than or equal to 0.40, preferably greater than or equal to 0.60, more preferably greater than or equal to 0.80, in particular greater than or equal to 1.0.

According to a preferred embodiment, said organic extractant is chosen from the group consisting of ethylamine, isopropylamine, diethylether, n-propylamine, diethylamine, propanone, methylacetate, butanone, diethoxymethane, isopropylacetate, 3-pentylamine, 2methoxyethanamine, tert- butylacetate, 1,4-dioxane, 1,1-diethoxyethane, trimethoxymethane, n-pentylamine, 1,3-dioxane, sec-butylacetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1,2propanediamine, n- butylacetate, 2-methoxy-1-propanol, hexanal. Preferably, said organic extractant is chosen from the group consisting of ethylamine, isopropylamine, diethylether, n-propylamine, diethylamine, diethoxymethane, isopropylacetate, 3-pentylamine, 2-methoxyethanamine, tert-butylacetate, 1,4-dioxane, 1,1-diethoxyethane, trimethoxymethane, n-pentylamine, 1,3-dioxane, sec-butylacetate, 1,2-diaminoethane, 1methoxy-2-propanol, 1,2-propanediamine, n-butylacetate, 2-methoxy-l- propanol, hexanal.

According to another aspect, the present invention provides a process for the production and purification of 2,3,3,3-tetrafluoro-1-propene comprising the steps of:

A) fluorination in the presence of a catalyst of a compound of formula CH ( _n +2) (X) _m CHp (X) (n + i) -CX (3 + pm) where X independently represents F or Cl; n, m, p are independently of each other 0 or 1 with (n + m) = 0 or 1, (n + p) = 0 or 1 and (mp) = 0 or 1, at least one X being Cl;

B) recovery of a stream comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2pentafluoropropane (245cb), trans-l, 3,3,3-tetrafluoro-l- propene (1234ze-E), and optionally or not at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene ( 1243zf);

C) implementation of the process for purifying 2,3,3,3-tetrafluoro-1-propene according to the present invention from the stream recovered in step B).

Brief description of the figures

FIG. 1 diagrammatically represents a device implementing a process for producing 2,3,3,3-tetrafluoro-1-propene according to a particular embodiment of the present invention.

FIGS. 2a-d schematically represent a device implementing a process for the purification of 2,3,3,3-tetrafluoro-l-propene according to a particular embodiment of the present invention.

Detailed description of the invention

The term "hydrocarbon" as used herein refers to linear or branched compounds of C1-C20 alkane, C3-C20 cycloalkane, C2-C20 alkene, C3-C20 cycloalkene, C6-C18 arene. For example, the term alkane refers to compounds of formula C _n H2n + 2 in which n is between 1 and 20. The term C1-C20 alkane includes for example pentane, hexane, heptane, octane, nonane, decane or isomers of these. The term C2-C20 alkene refers to hydrocarbon compounds comprising one or more carbon-carbon double bonds and comprising from 2 to 20 carbon atoms. The term C3-C20 cycloalkane refers to a saturated hydrocarbon ring comprising from 3 to 20 carbon atoms. The term Cg-Cigse aryl refers to cyclic and aromatic hydrocarbon compounds having 6 to 18 carbon atoms. The term C3-C20 cycloalkene refers to cyclic hydrocarbon compounds comprising from 3 to 20 carbon atoms and comprising one or more carbon-carbon double bonds.

The term "alkyl" denotes a monovalent radical derived from an alkane, linear or branched, comprising from 1 to 20 carbon atoms. The term "cycloalkyl" denotes a monovalent radical derived from a cycloalkane comprising from 3 to 20 carbon atoms. The term "aryl" denotes a monovalent radical originating from an arene comprising from 6 to 18 carbon atoms. The term "alkenyl" denotes a monovalent radical of 2 to 20 carbon atoms and at least one carbon-carbon double bond. The term "alkynyl" denotes a monovalent radical of 2 to 20 carbon atoms and at least one carbon-carbon triple bond. The term "halogen" refers to a group -F, -Cl, -Br or -I. The term "cycloalkenyl" refers to a monovalent radical derived from a cycloalkene comprising from 3 to 20 carbon atoms. The C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C3-C20 cycloalkyl, C3C20 cycloalkenyl, C6-C18 aryl substituents may or may not be substituted by one or more substituents -OH, halogen, -NR ^a C (O) R ^b , -C (O) NR ^a R ^b , -CN, -NO2, -NR ^a R ^b , -OR ^a , -SR ^a , -CO2R ^a , -OC (O) OR ^a , -OC (O) R ^a , C (O) H, -C (O) R ^a in which R ^a and R ^b are independently of each other hydrogen, alkyl in

Unsubstituted C1-C20, unsubstituted C2-C20 alkenyl, unsubstituted C2-C20 alkynyl, unsubstituted C3-C20 cycloalkyl, unsubstituted C3-C20 cycloalkenyl, unsubstituted C6-C18 aryl. In the substituents -NR ^a R ^b , -NR ^a C (O) R ^b , -C (O) NR ^a R ^b , R ^a and R ^b can form with the nitrogen atom or with the functional group to which they are attached a saturated or unsaturated heterocycle, aromatic or not, comprising from 4 to 10 links.

The term "hydrohalocarbons" refers to compounds of formula R ^a X in which R ^a is selected from C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C3C20 cycloalkyl, C3-C20 cycloalkenyl, C6-C18 aryl and X represents a chlorine, fluorine, bromine or iodine atom. The C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C3-C20 cycloalkyl, C3-C20 cycloalkenyl, Cg-C18 aryl substituents may or may not be substituted by one or more substituents -OH, halogen, -NR ^a C (O) R ^b , -C (O) NR ^a R ^b -CN, -NO2, -NR ^a R ^b , -OR ^a , SR ^a , -CÛ2R ^a , -OC (O) OR ^a , -OC (O) R ^a , -C (O) H, -C (O) R ^a in which R ^a and R ^b are as defined above.

The term "alcohol" refers to hydrocarbons or hydrohalocarbons as defined above in which at least one hydrogen atom is replaced by a hydroxyl group -OH.

The term "ketone" refers to hydrocarbons comprising at least one or more carbonyl functional groups R ^c -C (O) -R ^d in which R ^c and R ^d are, independently of one another, C1- C20, C2-C20 alkenyl, C2-C20 alkynyl, C3-C20 cycloalkyl, C3-C20 cycloalkenyl, Cg-C18 aryl may or may not be substituted by one or more substituents -OH, halogen, -NR ^to C (O) R ^b , -C (O) NR ^a R ^b -CN, -NO2, -NR ^a R ^b , -OR ^a , -SR ^a , -CO2R ^a , OC (O) OR ^a , -OC (O ) R ^a , -C (O) H, -C (O) R ^a in which R ^a and R ^b are as defined above, R ^c and R ^d being able to be linked together to form with the carbonyl group to which they are attached a cyclic ketone comprising from 4 to 10 links, preferably from 4 to 7 links. The cyclic ketone can also include one or more carbon-carbon double bonds. The cyclic ketone can also be substituted or not by one or more substituents as defined above.

The term "amine" refers to hydrocarbons comprising at least one or more amine functional groups -NR ^c R ^d in which R ^c and R ^d are as defined above, R ^c and R ^d can be linked together to form with the nitrogen atom to which they are attached an aromatic or non-aromatic heterocycle comprising from 4 to 10 links.

The term “esters” refers to compounds of formula R ^c -C (O) -OR ^d in which R ^c and R ^d are as defined above, R ^c and R ^d can be linked together to form with the ester group a ring comprising from 4 to 20 carbon atoms.

The term "ether" refers to compounds of formula R ^c -OR ^d in which R ^c and R ^d are as defined above, R ^c and R ^d can be linked together to form with the atom d ' oxygen to which they are attached a heterocycle comprising from 4 to 20 carbon atoms.

The term "aldehyde" refers to compounds comprising at least one or more functional groups -C (O) -H.

The term "nitrile" refers to compounds comprising at least one or more functional groups -CN.

The term "carbonate" refers to compounds of formula R ^c -OC (O) -OR ^d in which R ^c and R ^d are as defined above.

The term "thioalkyl" relates to compounds of formula R ^c SR ^d in which R ^c and R ^d are as defined above.

The term “amide” relates to compounds of formula R ^c C (O) NR ^e R ^d in which R ^c and R ^d are as defined above, R ^e being chosen from the same substituents as those defining R ^c , R ^c and R ^d can be linked together to form, with the amide group C (O) N- to which they are attached, a cyclic amide comprising from 4 to 10 members, preferably from 4 to 7 members. The cyclic amide can also include one or more carbon-carbon double bonds. The cyclic amide may also be substituted or not by one or more substituents as defined above.

The term “heterocycle” designates a carbon ring comprising from 4 to 10 links, at least one of the links is a heteroatom selected from the group consisting of O, S, P and N. The heterocycle can comprise one or more carbon double bond- carbon or one or more carbon-hetero atom double bond or one or more hetero atom hetero atom double bond. Preferably, the heterocycle can comprise 1, 2, 3, 4 or 5 heteroatoms as defined above. In particular, the heterocycle can comprise 1, 2 or 3 heteroatoms selected from oxygen, nitrogen or sulfur. Preferably, the heterocycle can be a carbon ring comprising from 4 to 6 members, of which 1, 2 or 3 members are heteroatoms selected from O or N. The heterocycle may or may not be substituted by one or more substituents chosen from -OH , halogen, -NR ^a C (O) R ^b , -C (O) NR ^a R ^b -CN, -NO2, -NR ^a R ^b , -OR ^a , -SR ^a , COîR ³ , -OC (O) OR ^a , -OC (O) R ^a , -C (O) H, -C (O) R ^a in which R ^a and R ^b are as defined above.

The term "organic extractant" refers to a compound having at least one carbon atom.

According to a first aspect, the invention relates to a process for the purification of 2,3,3,3tetrafluoro-1-propene (1234yf). The purification process is carried out using a first composition comprising 2,3,3,3-tetrafluoro-1-propene, 1,1,1,2,2-pentafluoropropane (245cb) and trans-1,3, 3,3-tetrafluoro-l-propene (1234ze-E).

Preferably, said method comprises the steps of:

a) bringing said first composition into contact with at least one organic extracting agent to form a second composition;

b) extractive distillation of said second composition to form:

i) a third composition comprising said organic and trans-1,3,3,3-tetrafluoro-1-propene extractant (1234ze-E) and ii) a stream comprising 2,3,3,3-tetrafluoro- l-propene and 1,1,1,2,2pentafluoropropane (245cb),

c) recovery and separation of said third composition to form a stream comprising said organic extractant and a stream comprising trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E).

Preferably, the first composition is obtained from a mixture C comprising 2,3,3,3-tetrafluoro-1-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans1.3.3.3 - tetrafluoro-l-propene (1234ze-E) and HF, said mixture being subjected to the following stages:

i ') bringing said mixture C into contact with an aqueous solution of hydrofluoric acid of concentration greater than 40% by weight to form a two-phase current comprising

2.3.3.3- tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans-l, 3,3,3-tetrafluoro1-propene (1234ze-E) and HF, ii ') storage of said second two-phase current in a buffer tank, said two-phase current consisting of a liquid phase and a gas phase, iii ') passage of said gaseous phase from said second two-phase current in an absorption column fed against the current by an aqueous stream to form a current Cl comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans1.3.3.3- tetrafluoro-l-propene ( 1234ze-E) and a current C2 including HF.

Preferably, the aqueous hydrofluoric acid solution used in step i ') has a concentration greater than 40% by weight. In particular, the aqueous hydrofluoric acid solution has a concentration greater than 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52% , 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69 %, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94% or 95% by weight. More particularly, the aqueous hydrofluoric acid solution is of concentration greater than or equal to 50% by weight, or greater than or equal to 60% by weight or greater than or equal to 70% by weight.

More particularly, the aqueous hydrofluoric acid solution can be between any of the values mentioned above. Thus, the aqueous hydrofluoric acid solution can be between 45% and 95% by weight, between 50% and 90% by weight, between 55% and 85% by weight, between 60% by weight and 80% by weight or between 65% by weight and 75% by weight.

Step i ′) of the present process allows the formation of said second two-phase current comprising 2,3,3,3-tetrafluoro-1-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans1,3, 3,3-tetrafluoro-1-propene (1234ze-E) and HF. Said two-phase current consists of a gas phase and a liquid phase. The gas phase can comprise 2,3,3,3-tetrafluoro-l-propene,

1,1,1,2,2-pentafluoropropane (245cb), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E). Optionally, the gas phase can comprise hydrofluoric acid. When the gas phase comprises hydrofluoric acid, the content of the latter is generally low, preferably less than 5% by weight based on the total weight of said gas phase, in particular less than 2% by weight based on the total weight of said gas phase, more particularly less than 1% by weight based on the total weight of said gas phase.

The liquid phase of said two-phase current can comprise hydrofluoric acid. Said liquid phase may optionally comprise a small amount of 2,3,3,3tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb) or trans-1,3,3,3-tetrafluoro-lpropene (1234ze-E), preferably said liquid phase may comprise a content of 2,3,3,3tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb) or trans-1,3,3 , 3-tetrafluoro-lpropene (1234ze-E) less than 5% by weight based on the total weight of said liquid phase, in particular less than 1% by weight based on the total weight of said liquid phase, more particularly less than 5000 ppm by weight based on the total weight of said liquid phase, preferably less than 1000 ppm by weight based on the total weight of said liquid phase, more preferably less than 500 ppm by weight, particularly preferably less than 100 ppm based on the total weight of said liquid phase. Said liquid phase may comprise a total content of 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2pentafluoropropane (245cb) and trans-l, 3,3,3-tetrafluoro-l- propene (1234ze-E) less than 5% by weight based on the total weight of said liquid phase, in particular less than 1% by weight based on the total weight of said liquid phase, more particularly less than 5000 ppm by weight based of the total weight of said liquid phase, preferably less than 1000 ppm by weight based on the total weight of said liquid phase, more preferably less than 500 ppm by weight, particularly preferably less than 100 ppm based on weight total of said liquid phase. Preferably, the concentration of hydrofluoric acid in said liquid phase of said second two-phase current is greater than the concentration of said aqueous solution of hydrofluoric acid used in step i '). Said liquid phase of said second two-phase current may have a hydrofluoric acid concentration greater than 41% by weight based on the total weight of said liquid phase of said second two-phase current. Advantageously, said liquid phase of said second two-phase current can be having a hydrofluoric acid concentration greater than 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52 %, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85% , 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94% or 95% by weight based on the total weight of said liquid phase of said second two-phase current. Preferably, said liquid phase of said second two-phase current can be having a hydrofluoric acid concentration of between 45% and 95% by weight, between 50% and 90% by weight, between 55% and 85% by weight, between 60% by weight weight and 80% by weight or between 65% by weight and 75% by weight while being greater than the concentration of said aqueous hydrofluoric acid solution used in step i ').

Preferably, the aqueous hydrofluoric acid solution used in step i ') is at a temperature between -20 ° C to 80 ° C before being brought into contact with said mixture C, advantageously between -15 ° C and 70 ° C, preferably between -10 ° C and 60 ° C, more preferably between -5 ° C and 50 ° C, in particular between -5 ° C and 40 ° C, more particularly between 0 ° C and 30 ° C. Thus, in a particularly preferred embodiment, the temperature of the aqueous hydrofluoric acid solution used in step i '), before it is brought into contact with said mixture C, can be 0 ° C, 1 ° C, 2 ° C, 3 ° C, 4 ° C, 5 ° C, 6 ° C, 7 ° C, 8 ° C, 9 ° C, 10 ° C, 11 ° C, 12 ° C, 13 ° C, 14 ° C, 15 ° C, 16 ° C, 17 ° C, 18 ° C, 19 ° C, 20 ° C, 21 ° C, 22 ° C, 23 ° C, 24 ° C, 25 ° C, 26 ° C, 27 ° C, 28 ° C,

29 ° C or 30 ° C. The purpose of using said aqueous hydrofluoric acid solution at the temperatures mentioned above is to control the exothermicity occurring when it is brought into contact with said mixture C.

As mentioned above, step ii ′) of the method according to the present invention implements the storage of said second two-phase current in a buffer tank, said second two-phase current consisting of said liquid phase and said gaseous phase as described above.

As mentioned above, step iii ′) of the method according to the present invention implements the passage of said gaseous phase from said second two-phase current through an absorption column supplied against the current by an aqueous flow to form a current Cl comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans1,3,3,3-tetrafluoro-l-propene (1234ze-E) and a current C2 comprising HF.

Preferably, the flow rate of the aqueous flow used in step iii ') is determined as a function of the quantity of hydrofluoric acid contained in said mixture C. Thus, the ratio between the flow rate of the aqueous flow expressed in kg / h feeding the absorption column in step iii ') and the quantity of hydrofluoric acid in said mixture C expressed in kg / h is between 0.05 and 1.22. Advantageously, the ratio between the flow rate of the aqueous stream supplying the absorption column in step (iii) and the quantity of hydrofluoric acid in said mixture C expressed in kg / h can be between 0.11 and 1.00 , preferably between 0.18 and 0.82, more preferably between 0.25 and 0.67, in particular between 0.33 and 0.54. Thus the ratio between the flow rate of the aqueous stream supplying the absorption column in step (iii) and the quantity of hydrofluoric acid in said mixture C expressed in kg / h can be 0.25, 0.26, 0 , 27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34,

0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0, 47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68,

0.69 or 0.70. An additional aqueous stream corresponding to the fraction of water vaporized at the head of said absorption column can also feed said column. The aqueous stream as described above is different from said additional aqueous stream linked to the fraction of water vaporized at the top of the column and does not include it.

According to a preferred embodiment, said absorption column implemented in step iii ′) comprises at least one absorption stage. Advantageously, said absorption column implemented in step iii ′) comprises at least two absorption stages. Preferably, said absorption column implemented in step iii ′) comprises at least three absorption stages. Said absorption column implemented in step iii ′) can thus comprise two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen or fifteen absorption stages.

The use of an absorption column having at least one absorption stage, advantageously at least two absorption stages, preferably at least three absorption stages, makes it possible to obtain a current Cl having a low content hydrofluoric acid. Advantageously, said stream C1 comprises less than 1000 ppm of hydrofluoric acid by weight based on the total weight of said third stream, preferably less than 900 ppm of hydrofluoric acid, more preferably less than 800 ppm of hydrofluoric acid, in particular less of 700 ppm hydrofluoric acid, more particularly less than 600 ppm of hydrofluoric acid, preferably less than 500 ppm of hydrofluoric acid, even more preferably less than 400 ppm of hydrofluoric acid, preferentially less of 300 ppm of hydrofluoric acid, in a particularly preferred manner less than 200 ppm of hydrofluoric acid, more particularly preferred less than 100 ppm of hydrofluoric acid. Thus, said third stream can have a hydrofluoric acid content between 1 and 200 ppm, between 5 and 190 ppm, between 10 and 180 ppm, between 15 and 170 ppm, between 20 and 160 ppm, between 25 and 150 ppm or between 30 and 140 ppm by weight based on the total weight of said stream Cl.

Preferably, at least 80% by weight of the hydrofluoric acid possibly present in said gas phase of said second two-phase stream is absorbed by the first absorption stage of said absorption column, in particular at least 85% by weight of l hydrofluoric acid possibly present in said gas phase of said second two-phase current is absorbed by the first absorption stage of said absorption column, more particularly at least 90% by weight of hydrofluoric acid possibly present in said gas phase of said second two-phase current is absorbed by the first absorption stage of said absorption column.

Preferably, said aqueous stream can be introduced at least at the head of the absorption column.

According to a particular embodiment, said current C1 can be said first composition according to the present invention.

According to a preferred embodiment, said stream C2 is in the form of an aqueous solution of hydrofluoric acid. Advantageously, said stream C2 is a hydrofluoric acid solution with a concentration of less than 30% by weight based on the total weight of said fourth stream. Preferably, said stream C2 is a hydrofluoric acid solution with a concentration of less than 25% by weight based on the total weight of said stream C2. In particular, said stream C2 is a hydrofluoric acid solution with a concentration of between 5 and 25% by weight based on the total weight of said stream C2, more particularly, between 10 and 20% by weight based on the total weight of said stream C2 . According to a preferred embodiment, said stream C2 is recycled in step ii '). Current C2 can thus be mixed with said liquid phase of said second two-phase current.

According to a preferred embodiment, said method also comprises the steps of: iv ') neutralization of said stream C1 obtained in step iii') with an aqueous alkaline solution to form a neutralized stream C3, and ν ') drying of said neutralized stream C3 obtained in step iv ') on a molecular sieve to form a neutralized and dried stream C4 comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2pentafluoropropane (245cb), trans- 1, 3,3,3-tetrafluoro-1-propene (1234ze-E).

According to a preferred embodiment, said alkaline aqueous solution can be an aqueous hydroxide solution of an alkali or alkaline earth metal. The alkaline aqueous solution can be an aqueous solution of sodium hydroxide, potassium hydroxide, calcium hydroxide or magnesium hydroxide or a mixture thereof. Preferably, said alkaline aqueous solution has a concentration of between 5 and 50% by weight based on the total weight of said aqueous alkaline solution. Advantageously, said alkaline aqueous solution has a concentration of at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, at least 10% , at least 11%, at least 12%, at least 13%, at least 14%, at least 15%, at least 16% or at least 17% in weight based on the total weight of said alkaline aqueous solution; and not more than 50%, not more than 48%, not more than 46%, not more than 44%, not more than 42%, not more than 40%, not more than 38%, not more than 36%, not more than 34%, not more than 32%, not more than 30%, not more than 28%, not more than 26%, not more than 24%, d '' at most 22% by weight based on the total weight of said alkaline aqueous solution.

Said neutralized current C3 formed in step iv ′) preferably comprises 2,3,3,3tetrafluoro-1-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans-1, 3,3, 3-tetrafluoro-lpropene (1234ze-E). The hydrofluoric acid content in said neutralized current C3 is lower than the hydrofluoric acid content of said Cl, before its neutralization. Said neutralized current C3 formed in step iv ') may also contain water.

Said neutralized current C3 formed in step iv ') can thus be dried in step ν') of the present process. Preferably, said neutralized stream C3 formed in step iv ') is dried over a molecular sieve. For example, said neutralized current C3 formed in step iv ') is dried over a 3A molecular sieve, such as siliporite.

Step ν ') of the present process allows the formation of a neutralized and dried current C4 comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans1.3.3.3- tetrafluoro-l-propene (1234ze-E). Said stream C4 can then be compressed and liquefied at a pressure of at most 8 bara to form a stream C5 compressed in which

2.3.3.3- tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans-l, 3,3,3-tetrafluoro1-propene (1234ze-E) are in liquid form.

According to a particular embodiment, the stream C4 or the stream C5 can be said first composition according to the present invention.

According to a preferred embodiment, the liquid phase resulting from the mixing of said liquid phase of said second two-phase stream with said stream C2 is recycled in step i ').

The liquid phase resulting from the mixture of said liquid phase of said second two-phase stream with said stream C2 may have a hydrofluoric acid concentration greater than 41% by weight based on the total weight of said liquid phase resulting from the mixing of said liquid phase of said second stream two-phase with said current C2. Advantageously, the liquid phase resulting from the mixing of said liquid phase of said second two-phase stream with said stream C2 may have a hydrofluoric acid concentration greater than 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65% , 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82 %, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94% or 95% by weight based on the total weight of the said phase liquid resulting from the mixing of said liquid phase of said second two-phase stream with said stream C2. Preferably, the liquid phase resulting from the mixing of said liquid phase of said second two-phase stream with said stream C2 may have a hydrofluoric acid concentration of between 45% and 95% by weight, between 50% and 90% by weight, between 55% and 85% by weight, between 60% by weight and 80% by weight or between 65% by weight and 75% by weight based on the total weight of said liquid phase resulting from the mixing of said liquid phase of said second two-phase current with said current C2.

According to another preferred embodiment, the liquid phase resulting from the mixing of said liquid phase of said second two-phase stream with said stream C2 is distilled to form a stream D, preferably at the top of the distillation column. Advantageously, said stream D comprises hydrofluoric acid containing less than 3000 ppm of water, preferably less than 2000 ppm of water, more preferably less than 1000 ppm of water, in particular less than 500 ppm of water, more particularly less than 200 ppm of water, preferably less than 100 ppm of water, more preferably less than 50 ppm of water based on the total weight of stream D. Said stream D may also include less than 50 ppm hydrochloric acid, advantageously less than 45 ppm hydrochloric acid, preferably less than 40 ppm hydrochloric acid, more preferably less than 35 ppm hydrochloric acid, in particular less than 30 ppm hydrochloric acid, more particularly less than 20 ppm of hydrochloric acid based on the total weight of stream D Said stream D may also comprise less than 50 ppm of organic compounds, advantageously less than 45 ppm of organic compounds, preferably less than 40 p pm of organic compounds, more preferably less than 35 ppm of organic compounds, in particular less than 30 ppm of organic compounds, more particularly less than 20 ppm of organic compounds based on the total weight of the stream D. An organic compound is a compound comprising at least one carbon atom.

In addition, the distillation of said liquid phase resulting from the mixing of said liquid phase of said second two-phase stream with said stream C2 forms a stream E, preferably at the bottom of the distillation column, comprising hydrofluoric acid in the form of a solution. aqueous concentration of less than 50% by weight. Advantageously, said stream E comprising hydrofluoric acid in the form of an aqueous solution of concentration of less than 50% by weight, 49% by weight, 48% by weight, 47% by weight, 46% by weight, 45% by weight, 44% by weight, 43% by weight, 42% by weight based on the total weight of said stream E. Preferably, said stream E comprising hydrofluoric acid in the form of an aqueous solution of concentration greater than 20% by weight based on the total weight of said stream E. In particular, said stream E comprising hydrofluoric acid in the form of an aqueous solution of higher concentration 21% by weight, 22% by weight, 23% by weight, 24% by weight, 25% by weight, 26% by weight, 27% by weight, 28% by weight, 29% by weight, 30% by weight, 31% by weight, 32% by weight, 33% by weight, 34% by weight, 35% by weight based on the total weight of said stream E. Said aqueous solution obtained in stream E can be marketed or destroyed by neutralization.

The liquid phase resulting from the mixing of said liquid phase of said second two-phase stream with said stream C2 can thus be either distilled or recycled in step i '). Preferably, part of the liquid phase resulting from the mixing of said liquid phase of said second two-phase stream with said stream C2 is distilled while the other part of the liquid phase resulting from the mixing of said liquid phase of said second two-phase stream with said stream C2 is recycled in step i '). Preferably, at least 50%, more preferably at least 60%, in particular at least 70%, more particularly at least 80%, in a preferred manner at least 90% by weight of the liquid phase resulting from the mixing of said liquid phase of said second two-phase current with said current C2 is recycled in step i '); and less than 50%, preferably less than 40%, more preferably less than 30%, in particular less than 20%, more particularly less than 10% by weight is distilled.

Preferably, the stream comprising said organic extraction agent is recycled in step a). Preferably, the stream comprising trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E) is purified or destroyed by incineration.

Preferably, said method also comprises a step of recovering said stream comprising 2,3,3,3-tetrafluoro-l-propene (1234yf) and 1,1,1,2,2pentafluoropropane (245cb) obtained in step b), and distillation thereof to form a stream A comprising 2,3,3,3-tetrafluoro-1-propene and a stream B comprising 1,1,1,2,2pentafluoropropane (245cb).

Said first composition, the mixture C, the current Cl, the current C3, the current C4 and / or the current C5 can (come) t 2,3,3,3-tetrafluoro-l-propene, 1,1, 1,2,2pentafluoropropane (245cb), trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E) and at least one of the compounds selected from the group consisting of chloromethane (40), 1,1- difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3pentafluoropropene (1225ye-E), cis-l, 2,3,3, 3-pentafluoropropene (1225ye-Z), 3,3,3trifluoropropene (1243zf). Preferably, said first composition, the mixture C, the stream Cl, the stream C3 and / or the stream C4 can (at least) comprise at least two, at least three, at least four, at least five, at least six or all of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3 , 3,3-pentafluoropropene (1225ye-E), cis1,2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf).

When Said first composition, the mixture C, the current C1, the current C3, the current C4 and / or the current C5 contains (nen) t at least one of the compounds selected from the group consisting of chloromethane (40), 1,1 -difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), cis3064629

1,2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf), the latter or these are contained in said second and third compositions.

Step c) of the present process can thus consist in the recovery of said third composition and the separation between on the one hand said organic extracting agent and on the other hand trans-l, 3,3,3-tetrafluoro- l-propene (1234ze-E) and said at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2tetrafluoroethane (134a), chloropentafluoroethane (115) , trans-1,2,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf).

Said first composition, mixture C, stream C1, stream C3, stream C4 and / or stream C5 can (come) from 50 to 99% by weight of 2,3,3,3-tetrafluoro-lpropene based on the total weight of the first composition, advantageously between 50 and 95% by weight, preferably between 55 and 90% and in particular between 60 and 80% by weight of 2,3,3,3tetrafluoro-l-propene on the basis of the total weight of the first composition.

Said first composition, mixture C, current Cl, current C3, current C4 and / or current C5 can (come) between 0.1 and 50% by weight of 1,1,1,2,2pentafluoropropane (245cb ) based on the total weight of the first composition, advantageously between 0.1 and 49.9% by weight, preferably between 1 and 45% by weight, more preferably between 2 and 40% and in particular between 5 and 40% by weight of 1,1,1,2,2pentafluoropropane (245cb) based on the total weight of the first composition.

Said first composition, the mixture C, the current Cl, the current C3, the current C4 and / or the current C5 can (come) between 0.1 and 50% by weight of trans-1,3,3,3tetrafluoro-l -propene (1234ze-E) based on the total weight of the first composition, advantageously between 0.1 and 49.9% by weight, preferably between 0.5 and 40% by weight, more preferably between 1 and 30% and in particular between 5 and 25% by weight of trans-1,3,3,3tetrafluoro-l-propene (1234ze-E) based on the total weight of the first composition.

Said first composition, the mixture C, the current Cl, the current C3, the current C4 and / or the current C5 can (come) less than 1% by weight of chloromethane (40) based on the total weight of the first composition , advantageously between 1 and 5000 ppm by weight, preferably between 5 and 2000 ppm and in particular between 10 and 1000 ppm by weight of chloromethane (40) based on the total weight of the first composition.

Said first composition, mixture C, stream Cl, stream C3, stream C4 and / or stream C5 can (come) less than 2000 ppm by weight of 1,1-difluoroethane (152a) based on the total weight of the first composition, advantageously between 1 and 1000 ppm by weight, preferably between 5 and 500 ppm and in particular between 10 and 250 ppm by weight of

1,1-difluoroethane (152a) based on the total weight of the first composition.

Said first composition, mixture C, current Cl, current C3, current C4 and / or current C5 can (come) less than 2000 ppm by weight of chloropentafluoroethane (115) based on the total weight of the first composition , advantageously between 1 and 1000 ppm by weight, preferably between 5 and 500 ppm and in particular between 10 and 250 ppm by weight of chloropentafluoroethane (115) based on the total weight of the first composition.

Said first composition, the mixture C, the current Cl, the current C3, the current C4 and / or the current C5 can (less) comprise less than 2000 ppm by weight of 1,1,1,2tetrafluoroethane (134a) on the basis of total weight of the first composition, advantageously between 1 and 1000 ppm weight, preferably between 5 and 500 ppm and in particular between 10 and 250 ppm weight of 1,1,1,2-tetrafluoroethane (134a) based on the total weight of the first composition.

Said first composition, the mixture C, the current Cl, the current C3, the current C4 and / or the current C5 can (come) less than 2000 ppm weight of trans-1,2,3,3,3pentafluoropropene (1225ye -E) based on the total weight of the first composition, advantageously between 1 and 1000 ppm by weight, preferably between 5 and 500 ppm and in particular between 10 and 250 ppm by weight of trans-l, 2,3,3,3- pentafluoropropene (1225ye-E) based on the total weight of the first composition.

Said first composition, the mixture C, the current Cl, the current C3, the current C4 and / or the current C5 can (less) comprise less than 2000 ppm weight of cis-1,2,3,3,3pentafluoropropene (1225ye -Z) based on the total weight of the first composition, advantageously between 1 and 1000 ppm by weight, preferably between 5 and 500 ppm and in particular between 10 and 250 ppm by weight of cis-1,2,3,3,3- pentafluoropropene (1225ye-Z) based on the total weight of the first composition.

Said first composition, mixture C, stream Cl, stream C3, stream C4 and / or stream C5 may (come) less than 1% by weight of 3,3,3-trifluoropropene (1243zf) based of the total weight of the first composition, advantageously between 1 and 5000 ppm by weight, preferably between 5 and 2000 ppm and in particular between 10 and 1500 ppm weight of

3,3,3-trifluoropropene (1243zf) based on the total weight of the first composition.

According to a particular embodiment, said organic extraction agent can be a solvent chosen from the group consisting of hydrohalocarbon, alcohol, ketone, amine, ester, ether, aldehyde, nitrile, carbonate, thioalkyl, amide, heterocycle; or the organic extractant is triethylfluorosilane. Preferably, the organic extraction agent is chosen from the group consisting of amine, ether, ester, aldehyde, ketone, alcohol and heterocycle.

Preferably, the hydrohalocarbons are selected from the group consisting of bromofluoromethane, l-bromo-l, 2-difluoroethylene, l, l, l-trifluoro-2-bromoethane, 2chloropropane, bromoethane, iodomethane, 2-chloro-2-methylpropane, 2-bromopropane, chlorobromomethane, 3-bromopropene, 1-bromopropane, iodoethane, 2-bromo-2methylpropane, l-chloro-3-fluoropropane, 2-chloro-2-methylbutane, 1,2-dichloroethane, 2iodopropane, dichlorobromomethane, 2- bromobutane, 1,2-dichloropropane, trichloroacetaldehyde, l-chloro-4-fluorobutane, l-bromo-3-fluoropropane, 1-bromobutane, 1iodopropane, cis-l, 3-dichloropropene, bromotrichloromethane, l-bromo-2-chloroethane, 2bromo-2-methylbutane, trans-1,3-dichloropropene, 1,1,2-trichloroethane, 2-bromopentane,

2.3- dichlorobutane, l-bromo-3-methylbutane, l, 3-dichloro-trans-2-butene, 1,3dichloropropane, 1,2-dibromo-l-fluoroethane, 1,2,2-trichloropropane, 2,3- dichloro-2methylbutane, 1-bromopentane, l, 2-dichloro-2-butene, 1-iodobutane, 1,2-dibromoethane,

1.1.2- trichloropropane, 1,3-dichlorobutane, 1,2-dibromopropane, 1,2,3-trichloropropene, 1chloro-3-bromopropane, tribromomethane.

Preferably, the alcohols are selected from the group consisting of methanol,

2.2.2- trifluoroethanol, l, l, l-trifluoro-2-propanol, ethanol, 2-propanol, tert-butanol, 2,2difluoroethanol, propanol, 2-allyloxyethanol, 2-butanol, 2-methyl-2-butanol, isobutanol,

2.2.3.3- tetraflouro-l-propanol, 2,2-dimethyl-l-propanol, 3-pentanol, 1-butanol, l-methoxy2propanol, l- (dimethylamino) -2-propanol, 3-methyl-3-pentanol, l-chloro-2-methyl-2-propanol, 4,4,4-trifluorobutanol, 3-fluoropropanol, 2-chloroethanol, 2-methoxyl-propanol, l-ethoxy-2propanol, 4-methyl-2-pentanol, 1, 2-octanediol, 2-chloro-l-propanol, 2- (dimethylamino) ethanol, 3-hexanol, 2-hexanol, 2-ethoxy-l-propanol, 1-pentanol, 2,3-dimethylbutanol, 2-ethyl1-butanol , 2-methyl-l-pentanol, 2-propoxyethanol.

Preferably, the ketones are selected from the group consisting of 1,1,1 trifluoro-2-propanone, propanone, butanone, 3-pentanone, 2-pentanone, 3,3-dimethyl-2butanone, 4-methyl-2-pentanone, 2-hexanone, 5-hexen-2-one, 4-methyl-2-hexanone.

Preferably, the amines are selected from the group consisting of Ethylamine, isopropylamine, ethylmethylamine, 2-amino-2-methylpropane, n-propylamine, isopropylmethylamine, diethylamine, 2-butanamine, n-methylpropylamine, 1-butylamine, diisopropylamine, 3- methyl-2-butanamine, 3-pentylamine, n-methylbutylamine, l-methoxy-23064629 propanamine, 2-methoxyethanamine, 2-methoxy-lpropanamine, n-pentylamine, nmethylhydroxylamine, dipropylamine, 2-ethoxyethanamine, n-methyl-l, 2 -ethanediamine, pyridine, 1,2-diaminoethane, 1,2-propanediamine, 2-ethylbutylamine, n-ethylethylenediamine,

1.1- diethoxy-n, n-dimethylmethanamine, 2-methylpyridine, 4-methyl-2-hexanamine, hexylamine, cyclohexylamine, n-ethyl-2-dimethylaminoethylamine, 1,3-propanediamine, 2heptanamine, n, n-diethylethylenediamine, 2, 6-dimethylpyridine, 4-methylpyridine, n, n'diethyl-l, 2-ethanediamine.

Preferably, the esters are selected from the group consisting of Methylformate, methylacetate, isopropylformate, ethylacetate, n-propylformate, isopropylacetate, tertbutylacetate, ethylpropionate, sec-butylacetate, diethylcarbonate, n-butylacetate, bromoaceticacidmethylester, methylhexanoate.

Preferably, the ethers are selected from the group consisting of 2,2,2trifluoroethylmethylether, 2-methoxy-l-propene, diethylether, ethoxy-ethene, dimethoxymethane, methylcyclopropylether, 2-ethoxy-propane, methyl-t-butylether, chloromethoxymethane, diisopropylether, 2-ethoxy-2-methyl-propane, 2-ethoxy-butane, 1methoxy-2-methyl-butane, 2,2-dimethoxypropane, l-ethoxy-2-methylpropane, 1,2dimethoxyethane, diethoxymethane, di-n- propylether, 1-ethoxybutane, 1-methoxy-pentane,

1.2- dimethoxypropane „isopropyl-isobutyl-ether, 1,1-diethoxyethane, trimethoxymethane,

2.2- diethoxypropane, isobutyl-tert-butylether, sec-butyl-tert-butylether, 1,1-diethoxypropane,

2- methoxyethanol, 2-chloro-l, l-dimethoxyethane, methoxycyclohexane, ethoxyethanol, di-nbutylether, 1-ethoxy-hexane, 1,1,1-triethoxyethane, l-methoxy-2-acetoxypropane.

Preferably, the aldehydes are selected from the group consisting of acetaldehyde, ethanedial, isobutanal, methylglyoxal, 2-methylbutanal, 2,6-dimethyl-5heptenal, hexanal.

Preferably, the nitriles are selected from the group consisting of acetonitrile, propionitrile, butyronitrile, valeronitrile, (methyleneamino) acetonitrile.

Preferably, the carbonate is diethylcaarbonate.

Preferably, the amide is ethanethioamide.

Preferably, the thioalkyls are selected from the group consisting of ethanethiol, dimethylsulfide, 2-propanethiol, 4-methoxy-2-methyl-2-butanethiol, tertbutylthiol, 1-propanethiol, 2-butanethiol, 2-methyl-l-propanethiol, diethylsulfide, butanethiol,

3- mercapto-1,2-propanediol, tetrahydrothiophene, 1-pentanethiol.

Preferably, the heterocycles are chosen from the group consisting of tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, 1,3,5-trioxane, n-methylmorpholine, 2methylpyrazine, n-ethyl-morpholine, 1-methylpiperazine, 1,2-epoxypropane, piperidine, 3furfural, 2,6-dimethylmorpholine.

Said organic extracting agent can be ethylamine, bromofluoromethane, 1bromo-l, 2-difluoroethylene, acetaldehyde, l, l, l-trifluoro-2-propanone, l, l, l-trifluoro-2bromoethane, 2,2,2- trifluoroethylmethylether, isopropylamine, methylformate, 2-methoxy-lpropene, diethylether, 1,2-epoxypropane, ethanethiol, ethoxy-ethene, ethylmethylamine, dimethylsulfide, 2-chloropropane, bromoethane, dimethoxymethane, iodomethane, 2-amino2-methylpropane, methylcyclopropyl propylamine, isopropylmethylamine, ethanedial, 2-chloro-2-methylpropane, 2-propanethiol, 2-ethoxy-propane, methyl-t-butylether, diethylamine, propanone, methylacetate, 4-methoxy-2-methyl-2-butanethiol, 2bromopropane, chloromethoxymethane, 2-butanamine, n-methylpropylamine, tert-butylthiol, isobutanal, methanol, tetrahydrofuran, 1-propanethiol, chlorobromomethane, isopropylformate, diisopropylether, 3-bromopropene, 1-bromopropane, methylglyoxal, iodoethane propane, 2-bromo-2-methylpropane, 2,2,2-trif luoroethanol, 1chloro-3-fluoropropane, l, l, l-trifluoro-2-propanol, 1-butylamine, ethylacetate, ethanol, butanone, n-propylformate, 2-ethoxy-butane, 2-propanol, acetonitrile, tert-butanol, 1methoxy-2-methyl-butane, 2,2-dimethoxypropane, 2-chloro-2-methylbutane, 1,2dichloroethane, l-ethoxy-2-methylpropane, diisopropylamine, 2-butanethiol, 1,2dimethoxyethane, 3-methyl-2- butanamine, diethoxymethane, 2-methyl-l-propanethiol, isopropylacetate, 2-iodopropane, di-n-propylether, 3-pentylamine, n-methylbutylamine, 2bromobutane, diethylsulfide, 1-ethoxybutane, l-methoxy-2-propanamine, 2- methylbutanal, 2methoxyethanamine, 2,2-difluoroethanol, 1,2-dichloropropane, propanol, tert-butylacetate, propionitrile, trichloroacetaldehyde, 2-allyloxyethanol, butanethiol, 1-methoxy-pentane, ethylpropionate, 2-butanol, 1,2-dimethoxyprop isopropyl-isobutyl-ether, l-chloro-4fluorobutane, l-bromo-3-fluoropropane, 1,4-dioxane, 1-bromobutane, 3-pentanone, 1,1diethoxyethane, 2-pentanone, 2-methyl-2-butanol, 1- iodopropane, 2-methoxy-lpropanamine, trimethoxymethane, cis-l, 3-dichloropropene, n-pentylamine, 3,3-dimethyl-2-butanone, 1,3dioxane, piperidine, l-bromo-2-chloroethane, isobutanol, 2- bromo-2-methylbutane, dipropylamine, 2,2,3,3-tetraflouro-l-propanol, 2-ethoxyethanamine, triethylfluorosilane, secbutylacetate, trans-l, 3-dichloropropene, 2,2-dimethyl-l-propanol, n- methyl-1,2ethanediamine, 2,2-diethoxypropane, 1,3,5-trioxane, pyridine, n-methylmorpholine, 33064629 pentanol, 4-methyl-2-pentanone, 1,2-diaminoethane, isobutyl-tert-butylether, 2bromopentane , butyronitrile, 1-butanol, 2,3-dichlorobutane, sec-butyl-tert-butylether, 1methoxy2-propanol, 1,2-propanediamine, 2,6-dimethyl-5-heptenal, l-bromo-3-methylbutane,

1.3- dichloro-trans-2-butene, 1,3-dichloropropane, l- (dimethylamino) -2-propanol, tetrahydrothiophene, 3-methyl-3-pentanol, 1,2-dibromo-l-fluoroethane, 1,1- diethoxypropane,

1,2,2-trichloropropane, l-chloro-2-methyl-2-propanol, 2-methoxyethanol, 4,4,4trifluorobutanol, 2-ethylbutylamine, diethylcarbonate, n-butylacetate, 1-pentanethiol, 2chloro-l, l- dimethoxyethane, 2-hexanone, n-ethylethylenediamine, 3-fluoropropanol, 5-hexen2-one, 2,3-dichloro-2-methylbutane, l, l-diethoxy-n, n-dimethylmethanamine, 2methylpyridine, 1-bromopentane, 2- methoxyl-propanol, l, 2-dichloro-2-butene, 1-iodobutane, hexanal, l-ethoxy-2-propanol, 1,2-dibromoethane, 4-methyl-2-pentanol, bromoaceticacidmethylester, 1,1,2- trichloropropane, 1,2-octanediol, 4-methyl-2-hexanamine, hexylamine, 2-chloro-l-propanol, methoxycyclohexane, 2- (dimethylamino) -ethanol, 1,3dichlorobutane, cyclohexylamine, n-ethyl-2-dimethylaminoethylamine, ethoxyethanol, 3hexanol, 2-hexanol, 2-methylpyrazine, 2-ethoxy-l-propanol, 1-pentanol, n-ethyl-morpholine, 1methylpiperazine, 1,3-propanediamine, di-n-butylether, valeronitrile, (methyleneamino) acetonitrile , 1,2-dibromopropane, 1,2,3-trichloropropene, 2-heptanamine,

2.3- dimethylbutanol, 1-ethoxy-hexane, l-chloro-3-bromopropane, n, n-diethylethylenediamine,

3- furfural, 2,6-dimethylpyridine, 4-methyl-2-hexanone, 1,1,1-triethoxyethane, l-methoxy-2acetoxypropane, 4-methylpyridine, n, n'-diethyl-l, 2-ethanediamine, 2 , 6-dimethylmorpholine, 2ethyl-l-butanol, 2-methyl-l-pentanol, methylhexanoate, 2-propoxyethanol, l-propoxy-2propanol, dimethylethanolamine.

Advantageously, said organic extracting agent can be ethylamine, bromofluoromethane, acetaldehyde, isopropylamine, methylformate, 2-methoxy-l-propene, diethylether, 1,2-epoxypropane, ethanethiol, ethoxy-ethene, ethylmethylamine, dimethylsulfide, bromoethane, dimethoxymethane, 2-amino-2-methylpropane, methylcyclopropylether, n-propylamine, isopropylmethylamine, 2-propanethiol, 2-ethoxypropane, methyl-t-butylether, diethylamine, propanone, methylacetate, 4-methoxy-2-methyl2-butanethiol, 2-bromopropane, 2-butanamine, n-methylpropylamine, tert-butylthiol, isobutanal, tetrahydrofuran, 1-propanethiol, isopropylformate, diisopropylether, 1bromopropane, methylglyoxal, 2-ethoxy-2-methyl-propane, 2-bromo-2-methylpropane, 1butylamine, ethylacetate butanone, n-propylformate, 2-ethoxy-butane, 2-propanol, tertbutanol, l-methoxy-2-methyl-butane, 2,2-dimethoxypropane, l-ethoxy-2-methylpropane, diisopropylamine, 2-butanethiol, 1, 2-dimethoxyethane, 3-methyl-2-butanamine, diethoxymethane, 2-methyl-l-propanethiol, isopropylacetate, 2-iodopropane, di-npropylether, 3-pentylamine, n-methylbutylamine, 2-bromobutane, diethylsulfide, 1ethoxybutane, l-methoxy-2-propanamine, 2-methylbutanal, 2-methoxyethanamine, propanol, tert-butylacetate, propionitrile, 2-allyloxyethanol, butanethiol, 1-methoxy-pentane, ethylpropionate, 2-butanol, 1,2-dimethoxypropane, isopropyl-isobutyl-ether, l-bromo-3fluoropropane, 1,4-dioxane, 1-bromobutane, 3-pentanone, 1,1-diethoxyethane, 2-pentanone, 2-methyl-2-butanol, 2-methoxy-lpropanamine, trimethoxymethane, n-pentylamine, 3,3dimethyl-2-butanone, 1,3- dioxane, piperidine, isobutanol, 2-bromo-2-methylbutane, dipropylamine, 2-ethoxyethanamine, sec-butylacetate, 2,2-dimethyl-l-propanol, n-methyl-1,2ethanediamine, 2,2-diethoxypropane, 1, 3,5-trioxane, pyridine, n-methylmorpholine, 3pentanol, 4-methyl-2-pentanone, 1,2-diaminoethane, isobutyl-tert-butylether, 2bromopentane, butyronitrile, 1-butanol, sec-butyl-tert-butylether, l-methoxy2-propanol, 1,2propan ediamine, 2,6-dimethyl-5-heptenal, l-bromo-3-methylbutane, l- (dimethylamino) -2propanol, tetrahydrothiophene, 3-methyl-3-pentanol, 1,1-diethoxypropane, 2-methoxyethanol, 2- ethylbutylamine, diethylcarbonate, n-butylacetate, 1-pentanethiol, 2-chloro-l, ldimethoxyethane, 2-hexanone, n-ethylethylenediamine, 5-hexen-2-one, l, l-diethoxy-n, ndimethylmethanamine, 2-methylpyridine, 1-bromopentane, 2-methoxyl-propanol, hexanal, 1ethoxy-2-propanol, 4-methyl-2-pentanol, 1,2-octanediol, 4-methyl-2-hexanamine, hexylamine, methoxycyclohexane, 2- (dimethylamino) - ethanol, cyclohexylamine, n-ethyl-2dimethylaminoethylamine, ethoxyethanol, 3-hexanol, 2-hexanol, 2-methylpyrazine, 2-ethoxy-lpropanol, 1-pentanol, n-ethyl-morpholine, 1-methylpiperazine, 1,3-propanediamine, di-nbutylether, valeronitrile, (methyleneamino) acetonitrile, 2-heptanamine, 2,3-dimethylbutanol, 1-ethoxy-hexane, n, n-diethylethylenediamine, 3-furfural, 2,6-dimethylpyridine, 4-methyl-2hexanone, 1 , 1,1-triethoxyethane, l-methoxy-2-acetoxypropan e, 4-methylpyridine, n, n'-diethyl1,2-ethanediamine, 2,6-dimethylmorpholine, 2-ethyl-l-butanol, 2-methyl-l-pentanol, methylhexanoate, 2-propoxyethanol, l-propoxy-2 -propanol, dimethylethanolamine

Preferably, said organic extracting agent can be ethylamine, acetaldehyde, isopropylamine, methylformate, diethylether, 1,2-epoxypropane, ethylmethylamine, dimethoxymethane, 2-amino-2-methylpropane, methylcyclopropylether, n-propylamine, isopropylmethylamine, 2-ethoxy -propane, methyl-t-butylether, diethylamine, propanone, methylacetate, 4-methoxy-2-methyl-2-butanethiol, 2-butanamine, n-methylpropylamine, isobutanal, tetrahydrofuran, isopropylformate, diisopropylether, 2-ethoxy-2-methyl -propane,

1- butylamine, ethylacetate, butanone, n-propylformate, 2-ethoxy-butane, l-methoxy-2methyl-butane, 2,2-dimethoxypropane, l-ethoxy-2-methylpropane, diisopropylamine, 1,2dimethoxyethane, 3-methyl- 2-butanamine, diethoxymethane, isopropylacetate, di-npropylether, 3-pentylamine, n-methylbutylamine, diethylsulfide, 1-ethoxybutane, l-methoxy-2propanamine, 2-methylbutanal, 2-methoxyethanamine, tert-butylacetate, propionitrile, 2allyloxyethanol methoxy-pentane, ethylpropionate, 1,2-dimethoxypropane, isopropylisobutyl-ether, 1,4-dioxane, 3-pentanone, 1,1-diethoxyethane, 2-pentanone, 2-methoxylpropanamine, trimethoxymethane, n-pentylamine, 3,3- dimethyl-2-butanone, 1,3-dioxane, piperidine, dipropylamine, 2-ethoxyethanamine, sec-butylacetate, n-methyl-1,2ethanediamine, 2,2-diethoxypropane, pyridine, n-methylmorpholine, 4-methyl-2- pentanone,

1,2-diaminoethane, isobutyl-tert-butylether, butyronitrile, sec-butyl-tert-butylether, 1methoxy2-propanol, 1,2-propanediamine, 2,6-dimethyl-5-heptenal, l- (dimethylamino) -2propanol, 3-methyl-3-pentanol, 1,1-diethoxypropane, 2-ethylbutylamine, diethylcarbonate, nbutylacetate, 2-hexanone, n-ethylethylenediamine, 5-hexen-2-one, l, l-diethoxy-n, ndimethylmethanamine, 2- methylpyridine, 2-methoxyl-propanol, hexanal, l-ethoxy-2-propanol,

4-methyl-2-hexanamine, hexylamine, methoxycyclohexane, 2- (dimethylamino) -ethanol, cyclohexylamine, n-ethyl-2-dimethylaminoethylamine, ethoxyethanol, 2-methylpyrazine, 2ethoxy-l-propanol, n-ethyl-morpholine, 1- methylpiperazine, 1,3-propanediamine, di-nbutylether, valeronitrile, 2-heptanamine, 1-ethoxy-hexane, n, n-diethylethylenediamine, 2,6dimethylpyridine, 4-methyl-2-hexanone, 1,1,1-triethoxyethane, l-methoxy-2-acetoxypropane,

4-methylpyridine, n, n'-diethyl-l, 2-ethanediamine, 2,6-dimethylmorpholine, methylhexanoate,

2- propoxyethanol, l-propoxy-2-propanol.

In particular, said organic extracting agent can be ethylamine, isopropylamine, diethylether, ethylmethylamine, 2-amino-2-methylpropane, n-propylamine, isopropylmethylamine, 2-ethoxy-propane, methyl-t-butylether, diethylamine, propanone, methylacetate , 2-butanamine, n-methylpropylamine, isobutanal, tetrahydrofuran, 1butylamine, ethylacetate, butanone, n-propylformate, 2,2-dimethoxypropane, l-ethoxy-2methylpropane, 1,2-dimethoxyethane, 3-methyl-2-butanamine, diethoxymethane , isopropylacetate, 3-pentylamine, n-methylbutylamine, 1-ethoxybutane, l-methoxy-2propanamine, 2-methylbutanal, 2-methoxyethanamine, tert-butylacetate, 1-methoxy-pentane, ethylpropionate, 1,2-dimethoxypropane, 1,4 -dioxane, 3-pentanone, 1,1-diethoxyethane, 2pentanone, 2-methoxy-lpropanamine, trimethoxymethane, n-pentylamine, 3,3-dimethyl-2butanone, 1,3-dioxane, piperidine, 2-ethoxyethanamine, sec-butylacetate , n-methyl-1,23064629 ethanediamine, 2,2-diethoxypropane, 4-methyl-2-pentanone, 1,2-diaminoethane, b utyronitrile, l-methoxy-2-propanol, 1,2-propanediamine, 2,6-dimethyl-5-heptenal, 1 (dimethylamino) -2-propanol, 1,1-diethoxypropane, 2-ethylbutylamine, diethylcarbonate, nbutylacetate, 2 -hexanone, n-ethylethylenediamine, 5-hexen-2-one, 2-methylpyridine, 2methoxyl-propanol, hexanal, l-ethoxy-2-propanol, 4-methyl-2, hexanamine, hexylamine, methoxycyclohexane, 2- (dimethylamino) -ethanol, cyclohexylamine, n-ethyl-2dimethylaminoethylamine, 2-methylpyrazine, 2-ethoxy-l-propanol, 1-methylpiperazine, 1,3propanediamine, di-n-butylether, valeronitrile, 2-heptanamine, 1-ethoxy-hexane, n , ndiethylethylenediamine, 2,6-dimethylpyridine, 4-methyl-2-hexanone, 1,1,1-triethoxyethane, 1methoxy-2-acetoxypropane, 4-methylpyridine, n, n'-diethyl-l, 2-ethanediamine, 2, 6dimethylmorpholine, methylhexanoate, 2-propoxyethanol, l-propoxy-2-propanol.

The organic extraction agent to be used can be selected according to the compounds present in said first composition. Thus, the organic extractant can be selected according to the separation factor and the absorption capacity established for a particular composition. In addition to these two criteria, the choice of organic extracting agent can optionally be based on other commercial or environmental criteria, such as for example the cost of the organic extracting agent, its availability on the market, its toxic or flammable properties. In addition, according to a particular embodiment, in order to optimize the operation of the distillation columns used in step b) and c) of the present process for the purification of 2,3,3,3-tetrafluoro-1-propene, the boiling point of the organic extracting agent can be from 0 ° C to 200 ° C, advantageously from 10 ° C to 190 ° C, preferably from 10 ° C to 180 ° C, in particular from 10 ° C at 170 ° C, more particularly from 10 ° C to 160 ° C, and preferably from 10 ° C to 150 ° C.

According to a preferred embodiment, said organic extraction agent has a separation factor Si, 2 greater than or equal to 1.1, said separation factor being calculated by the formula

If, 2 = (yi, s * Pl) / (y2, s * P2) in which yi, s represents the activity coefficient of 2,3,3,3-tetrafluoro-l-propene (1234yf) in said agent organic extraction with infinite dilution,

PI represents the saturated vapor pressure of 2,3,3,3-tetrafluoro-l-propene (1234yf),

72, s represents the activity coefficient of trans-l, 3,3,3-tetrafluoro-l-propene (1234zeE) in said organic extraction agent with infinite dilution,

P2 represents the saturated vapor pressure of trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E).

According to a preferred embodiment, said organic extraction agent has a separation factor Si, 2 greater than or equal to 1.1, said separation factor being calculated by the formula Si, 2 = (7i, s * P1) / (y2, s * P2) in which yi, s represents the activity coefficient of 1,1,1,2,2-pentafluoropropane (245cb) in said organic extraction agent with infinite dilution,

PI represents the saturated vapor pressure of 1,1,1,2,2-pentafluoropropane (245cb),

72, s represents the activity coefficient of trans-l, 3,3,3-tetrafluoro-l-propene (1234zeE) in said organic extraction agent with infinite dilution,

P2 represents the saturated vapor pressure of trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E).

According to a preferred embodiment, said organic extraction agent has:

- a separation factor Si, 2 greater than or equal to 1.1, said separation factor being calculated by the formula Si, 2 = (yi, s * Pl) / (y2, s * P2) in which yi, s represents the activity coefficient of 2,3,3,3-tetrafluoro-1-propene (1234yf) in said organic extraction agent with infinite dilution,

PI represents the saturation vapor pressure of 2,3,3,3-tetrafluoro-l-propene (1234yf), y2, s represents the activity coefficient of trans-l, 3,3,3-tetrafluoro-l-propene (1234zeE) in said organic extraction agent with infinite dilution,

P2 represents the saturated vapor pressure of trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E);

and

- a separation factor Si, 2 greater than or equal to 1.1, said separation factor being calculated by the formula Si, 2 = (yi, s * Pl) / (y2, s * P2) in which yi, s represents the activity coefficient of 1,1,1,2,2-pentafluoropropane (245cb) in said organic extraction agent with infinite dilution,

PI represents the saturated vapor pressure of 1,1,1,2,2-pentafluoropropane (245cb), y2, s represents the activity coefficient of trans-l, 3,3,3-tetrafluoro-l-propene (1234zeE ) in said organic extraction agent with infinite dilution,

P2 represents the saturated vapor pressure of trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E).

Advantageously, in both cases, the separation factor Si, 2 may be greater than or equal to 1.2, preferably greater than or equal to 1.4, more preferably greater than or equal to 1.6, in particular greater than or equal to 1.8, more particularly greater than or equal to 2.0.

According to a preferred embodiment, said organic extraction agent has an absorption capacity C2, s greater than or equal to 0.20, said absorption capacity being calculated by the formula C2, s = 1 / (72, s ) in which 72, s represents the activity coefficient of trans-1,3,3,3tetrafluoro-l-propene (1234ze-E) in said organic extraction agent with infinite dilution. Advantageously, the absorption capacity C2, s is greater than or equal to 0.40, preferably greater than or equal to 0.60, more preferably greater than or equal to 0.80, in particular greater than or equal to 1.0.

According to a preferred embodiment, said organic extracting agent can have a separation factor Si, 2 greater than or equal to 1.1, advantageously greater than or equal to 1.2, preferably greater than or equal to 1.4, more preferably greater than or equal to 1.6, in particular greater than or equal to 1.8 and more particularly greater than or equal to 2.0; and an absorption capacity C2, s greater than or equal to 0.20, advantageously greater than or equal to 0.40, preferably greater than or equal to 0.60, more preferably greater than or equal to 0.80, in particular greater than or equal to 1.0.

As trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E) is one of the main impurities to be removed, the separation factor and said absorption capacity can be calculated for the particular binary couple consisting of 2 , 3,3,3-tetrafluoro-l-propene and trans-1,3,3,3tetrafluoro-l-propene (1234ze-E) and / or 1,1,1,2,2-pentafluoropropane (245cb) and trans -1,3,3,3tetrafluoro-l-propene (1234ze-E). The separation factor Si, 2 makes it possible to determine the capacity of an organic extracting agent to separate two or more compounds. The absorption capacity C2, s makes it possible to determine the quantity of solvent to be used to obtain the separation between the compounds considered.

Said organic extraction agent can have a separation factor Si, 2 greater than or equal to 1.4, said separation factor being calculated by the formula Si, 2 = (7i, s * P1) / (72, s * P2 ) in which 71, _s represents the activity coefficient of 2,3,3,3-tetrafluoro-1-propene relative to said organic extractant, PI represents the saturated vapor pressure of 2,3,3,3tetrafluoro -l-propene, 72, s represents the activity coefficient of trans-1,3,3,3-tetrafluoro-lpropene in said organic extraction agent with infinite dilution, P2 represents the saturated vapor pressure of trans-l , 3,3,3-tetrafluoro-1-propene and / or said organic extractant may have a separation factor Si, 2 greater than or equal to 1.4, said separation factor being calculated by the formula Si, 2 = (yi, s * Pl) / (72, s * P2) in which 71, _s represents the activity coefficient of 1,1,1,2,2-pentafluoropropane (245cb) compared to said organic extractant , PI represented ente the saturated vapor pressure of 1,1,1,2,2pentafluoropropane (245cb), 72, s represents the activity coefficient of trans-1,3,3,3-tetrafluoro1-propene in said organic extractant at infinite dilution, P2 represents the saturated vapor pressure of trans-1,3,3,3-tetrafluoro-1-propene; and preferably said organic extracting agent can have an absorption capacity C2, s greater than or equal to 0.60, said absorption capacity being calculated by the formula C2, s = 1 / (72, s) in which 72, s represents the activity coefficient of trans-1,3,3,3-tetrafluoro-1-propene in said organic extraction agent with infinite dilution; said organic extraction agent can thus be ethylamine, acetaldehyde, isopropylamine, methylformate, diethylether, 1,2-epoxypropane, ethylmethylamine, dimethoxymethane, 2-amino-2-methylpropane, methylcyclopropylether, npropylamine, isopropylmethylamine, 2-ethoxy-propane, methyl -t-butylether, diethylamine, propanone, methylacetate, 4-methoxy-2-methyl-2-butanethiol, 2-butanamine, nmethylpropylamine, isobutanal, tetrahydrofuran, isopropylformate, diisopropylether, 2ethoxy-2-methyl-propane, 1-butylamine, ethylacetate , butanone, n-propylformate, 2-ethoxybutane, l-methoxy-2-methyl-butane, 2,2-dimethoxypropane, l-ethoxy-2-methylpropane, diisopropylamine, 1,2-dimethoxyethane, 3-methyl-2-butanamine , diethoxymethane, isopropylacetate, di-n-propylether, 3-pentylamine, n-methylbutylamine, diethylsulfide, 1ethoxybutane, l-methoxy-2-propanamine, 2-methylbutanal, 2-methoxyethanamine, tertbutylacetate, propionitrile, 2-allyloxyethanol 1 -pentane, ethylpropionate, 1,2dimethoxypropane , isopropyl-isobutyl-ether, 1,4-dioxane, 3-pentanone, 1,1-diethoxyethane, 2pentanone, 2-methoxy-lpropanamine, trimethoxymethane, n-pentylamine, 3,3-dimethyl-2butanone, 1,3-dioxane , piperidine, dipropylamine, 2-ethoxyethanamine, sec-butylacetate, nmethyl-l, 2-ethanediamine, 2,2-diethoxypropane, pyridine, n-methylmorpholine, 4-methyl-2pentanone, 1,2-diaminoethane, isobutyl-tert-butylether , butyronitrile, sec-butyl-tertbutylether, l-methoxy2-propanol, 1,2-propanediamine, 2,6-dimethyl-5-heptenal, 1 (dimethylamino) -2-propanol, 3-methyl-3-pentanol, 1, 1-diethoxypropane, 2-ethylbutylamine, diethylcarbonate, n-butylacetate, 2-hexanone, n-ethylethylenediamine, 5-hexen-2-one, 1,1diethoxy-n, n-dimethylmethanamine, 2-methylpyridine, 2-methoxyl-propanol, hexanal, 1ethoxy-2-propanol, 4-methyl-2-hexanamine, hexylamine, methoxycyclohexane, 2 (dimethylamino) -ethanol, cyclohexylamine, n-ethyl-2-dimethylaminoethylamine, ethoxyethanol, 2-methylpyrazine, 2-ethoxy-l-propanol , n-ethyl-morpholine, 13064629 methyl piperazine, 1,3-propanediamine, di-n-butylether, valeronitrile, 2-heptanamine, 1ethoxy-hexane, n, n-diethylethylenediamine, 2,6-dimethylpyridine, 4-methyl-2-hexanone, 1,1,1triethoxyethane, l-methoxy-2-acetoxypropane, 4-methylpyridine, n, n'-diethyl-l, 2ethanediamine, 2,6-dimethylmorpholine, methylhexanoate, 2-propoxyethanol, l-propoxy-2propanol.

Said organic extraction agent can have a separation factor Si, 2 greater than or equal to 1.6, said separation factor being calculated by the formula Si, 2 = (yi, s * Pl) / (y2, s * P2 ) in which yi, _s represents the activity coefficient of 2,3,3,3-tetrafluoro-l-propene relative to said organic extractant, Pl represents the saturated vapor pressure of 2,3,3,3tetrafluoro -l-propene, y2, s represents the activity coefficient of trans-l, 3,3,3-tetrafluoro-lpropene in said organic extraction agent with infinite dilution, P2 represents the saturated vapor pressure of trans-l , 3,3,3-tetrafluoro-1-propene and / or said organic extractant may have a separation factor Si, 2 greater than or equal to 1.6, said separation factor being calculated by the formula Si, 2 = (yi, s * Pl) / (y2, s * P2) in which yi, _s represents the activity coefficient of 1,1,1,2,2-pentafluoropropane (245cb) compared to said organic extractant , Pl repr feels the saturated vapor pressure of 1,1,1,2,2pentafluoropropane (245cb), y2, s represents the activity coefficient of trans-1,3,3,3-tetrafluoro1-propene in said organic extractant at infinite dilution, P2 represents the saturated vapor pressure of trans-1,3,3,3-tetrafluoro-1-propene; and preferably said organic extracting agent can have an absorption capacity C2, s greater than or equal to 0.80, said absorption capacity being calculated by the formula C2, s = l / (y2, s) in which y2, s represents the activity coefficient of trans-1,3,3,3-tetrafluoro-1-propene in said organic extraction agent with infinite dilution; said organic extraction agent can thus be ethylamine, isopropylamine, diethylether, ethylmethylamine, 2-amino-2-methylpropane, npropylamine, isopropylmethylamine, 2-ethoxy-propane, methyl-t-butylether, diethylamine, propanone, methylacetate, 2-butanamine , n-methylpropylamine, isobutanal, tetrahydrofuran, 1-butylamine, ethylacetate, butanone, n-propylformate, 2,2-dimethoxypropane, l-ethoxy-2methylpropane, 1,2-dimethoxyethane, 3-methyl-2-butanamine, diethoxymethane, isopropylacetate , 3-pentylamine, n-methylbutylamine, 1-ethoxybutane, l-methoxy-2propanamine, 2-methylbutanal, 2-methoxyethanamine, tert-butylacetate, 1-methoxy-pentane, ethylpropionate, 1,2-dimethoxypropane, 1,4-dioxane , 3-pentanone, 1,1-diethoxyethane, 2pentanone, 2-methoxy-lpropanamine, trimethoxymethane, n-pentylamine, 3,3-dimethyl-2butanone, 1,3-dioxane, piperidine, 2-ethoxyethanamine, sec-butylacetate, n -methyl-1,23064629 ethanediamine, 2,2-diethoxypropane, 4-methyl-2-pentanone, 1,2-diaminoethane, butyronitr ile, l-methoxy2-propanol, 1,2-propanediamine, 2,6-dimethyl-5-heptenal, 1 (dimethylamino) -2-propanol, 1,1-diethoxypropane, 2-ethylbutylamine, diethylcarbonate, nbutylacetate, 2-hexanone , n-ethylethylenediamine, 5-hexen-2-one, 2-methylpyridine, 2methoxyl-propanol, hexanal, l-ethoxy-2-propanol, 4-methyl-2, hexanamine, hexylamine, methoxycyclohexane, 2- (dimethylamino) -ethanol , cyclohexylamine, n-ethyl-2dimethylaminoethylamine, 2-methylpyrazine, 2-ethoxy-l-propanol, 1-methylpiperazine, 1,3propanediamine, di-n-butylether, valeronitrile, 2-heptanamine, 1-ethoxy-hexane, n, ndiethylethylenediamine , 2,6-dimethylpyridine, 4-methyl-2-hexanone, 1,1,1-triethoxyethane, 1methoxy-2-acetoxypropane, 4-methylpyridine, n, n'-diethyl-l, 2-ethanediamine, 2,6dimethylmorpholine, methylhexanoate, 2-propoxyethanol, l-propoxy-2-propanol.

Preferably, said organic extracting agent can be ethylamine, isopropylamine, diethylether, ethylmethylamine, 2-amino-2-methylpropane, n-propylamine, isopropylmethylamine, 2-ethoxy-propane, methyl-t-butylether, diethylamine, propanone, methylacetate , 2-butanamine, n-methylpropylamine, isobutanal, tetrahydrofuran, 1butylamine, ethylacetate, butanone, n-propylformate, 2,2-dimethoxypropane, l-ethoxy-2methylpropane, 1,2-dimethoxyethane, 3-methyl-2-butanamine, diethoxymethane , isopropylacetate, 3-pentylamine, n-methylbutylamine, 1-ethoxybutane, l-methoxy-2propanamine, 2-methylbutanal, 2-methoxyethanamine, tert-butylacetate, 1-methoxy-pentane, ethylpropionate, 1,2-dimethoxypropane, 1,4 -dioxane, 3-pentanone, 1,1-diethoxyethane, 2pentanone, 2-methoxy-lpropanamine, trimethoxymethane, n-pentylamine, 3,3-dimethyl-2butanone, 1,3-dioxane, piperidine, 2-ethoxyethanamine, sec-butylacetate , n-methyl-1,2ethanediamine, 2,2-diethoxypropane, 4-methyl-2-pentanone, 1,2-diaminoethane, butyroni trile, l-methoxy2-propanol, 1,2-propanediamine, 2,6-dimethyl-5-heptenal, 1 (dimethylamino) -2-propanol, 1,1-diethoxypropane, 2-ethylbutylamine, diethylcarbonate, nbutylacetate, 2-hexanone , n-ethylethylenediamine, 5-hexen-2-one, 2-methylpyridine, 2methoxyl-propanol, hexanal. In particular, said organic extracting agent can be ethylamine, isopropylamine, diethylether, ethylmethylamine, 2-amino-2-methylpropane, npropylamine, isopropylmethylamine, 2-ethoxy-propane, diethylamine, 2-butanamine, nmethylpropylamine, 1-butylamine, n -propylformate, 2,2-dimethoxypropane, l-ethoxy-2methylpropane, 3-methyl-2-butanamine, diethoxymethane, isopropylacetate, 3-pentylamine, n-methylbutylamine, 1-ethoxybutane, l-methoxy-2-propanamine, 2-methylbutanal , 2methoxyethanamine, tert-butylacetate, 1-methoxy-pentane, 1,2-dimethoxypropane, 1,43064629 dioxane,, 1-diethoxyethane, 2-methoxy-lpropanamine, trimethoxymethane, n-pentylamine,

1.3- dioxane, piperidine, 2-ethoxyethanamine, sec-butylacetate, n-methyl-l, 2-ethanediamine,

2,2-diethoxypropane, 1,2-diaminoethane, butyronitrile, l-methoxy2-propanol, 1,2propanediamine, 2,6-dimethyl-5-heptenal, l- (dimethylamino) -2-propanol, 1,1diethoxypropane, 2- ethylbutylamine, n-butylacetate, n-ethylethylenediamine, 5-hexen-2-one, 2-methylpyridine, 2-methoxyl-propanol, hexanal.

According to a preferred embodiment, said organic extracting agent can be ethylamine, isopropylamine, diethylether, n-propylamine, diethylamine, propanone, methylacetate, butanone, diethoxymethane, isopropylacetate, 3-pentylamine, 2methoxyethanamine, tert-butylacetate, 1,4 -dioxane, 1,1-diethoxyethane, trimethoxymethane, n-pentylamine, 1,3-dioxane, sec-butylacetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1,2propanediamine, n-butylacetate, 2-methoxy -l-propanol, hexanal. In particular, said organic extracting agent can be ethylamine, isopropylamine, diethylether, n-propylamine, diethylamine, diethoxymethane, isopropylacetate, 3-pentylamine, 2-methoxyethanamine, tertbutylacetate, 1,4-dioxane, 1,1-diethoxyethane, trimethoxymethane , n-pentylamine, 1,3dioxane, sec-butylacetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1,2-propanediamine, nbutylacetate, 2-methoxy-l-propanol, hexanal.

According to a preferred embodiment, said third composition comprising said organic and trans-1,3,3,3-tetrafluoro-1-propene extractant (1234ze-E); preferably the third composition comprising said organic and trans-1,3,3,3tetrafluoro-1-propene extractant (1234ze-E) and optionally or not at least one of the compounds chosen from the group consisting of chloromethane (40) , 1,1-difluoroethane (152a), 1,1,1,2tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3,3-pentafluoropropene (1225ye-E), cis-1,2 , 3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf); may be subjected to distillation to separate the organic extractant and trans-1,3,3,3tetrafluoro-1-propene (1234ze-E); preferably to separate on the one hand the organic extractant and on the other hand the trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) and optionally or not at least one of the compounds chosen from the group consisting of chloromethane (40), 1,1difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans1.2.3.3.3- pentafluoropropene (1225ye-E), cis -1,2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3trifluoropropene (1243zf). Said organic extraction agent is thus recycled in step a) of the purification process. The current comprising trans-1,3,3,3-tetrafluoro-1-propene (1234zeE) and optionally or not at least one of the compounds chosen from the group consisting of chloromethane (40), 1,1-difluoroethane (152a) , 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3,3pentafluoropropene ( 1225ye-Z), 3,3,3-trifluoropropene (1243zf) can either be subjected to one or more subsequent purification steps or can be destroyed by incineration.

The present process therefore makes it possible to purify 2,3,3,3-tetrafluoro-1-propene (1234yf). Advantageously, the content of trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E) in the stream comprising 2,3,3,3-tetrafluoro-l-propene (1234yf) and 1.1 , 1,2,2-pentafluoropropane (245cb) and obtained in step b) of the present purification process is less than the content of the latter in said first composition. Preferably, the content of trans-1,3,3,3-tetrafluoro-lpropene (1234ze-E) and / or at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane ( 152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3, 3pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf) in the stream comprising

2.3.3.3- tetrafluoro-l-propene (1234yf) and 1,1,1,2,2-pentafluoropropane (245cb) and obtained in step b) of the present purification process is lower than the content thereof in said first composition.

For example, the content of trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E) or any of the compounds selected from the group consisting of chloromethane (40), 1,1difluoroethane (152a ), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans1.2.3.3.3- pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z ), 3,3,3trifluoropropene (1243zf) can be reduced by 50%, advantageously by 75%, preferably by 90%, in particular by 95%, more particularly by 98%. Advantageously, the content of at least two, at least three, at least four, at least five, at least six or all of said compounds selected from the group consisting of chloromethane (40), 1,1difluoroethane (152a), 1 , 1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans1.2.3.3.3- pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3 , 3,3trifluoropropene (1243zf) can be reduced by 50%, advantageously by 75%, preferably by 90%, in particular by 95%, more particularly by 98%. Preferably, the content of trans1.3.3.3- tetrafluoro-l-propene (1234ze-E) can be reduced by 50%, advantageously by 75%, preferably by 90%, in particular by 95%, more particularly by 98 %.

Preferably, the stream comprising 2,3,3,3-tetrafluoro-1-propene and 1,1,1,2,2pentafluoropropane obtained in step b) of the present purification process can be free of trans-1, 3,3,3-tetrafluoro-1-propene (1234ze-E). In particular, the current comprising the

2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2-pentafluoropropane obtained in step b) of the present purification process can be devoid of trans-l, 3,3,3 -tetrafluoro-l-propene (1234ze-E) and / or optionally at least one, at least two, at least three, at least four, at least five, at least six or from all of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2 , 3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3,3pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf) when this or these are present in said first composition. The term "free" means that the stream comprising 2,3,3,3-tetrafluoro-l-propene (1234yf) comprises less than 50 ppm, advantageously less than 20 ppm, preferably less than 10 ppm of the compound considered on the basis of the total weight of the current. The contents are expressed by weight.

According to a preferred embodiment, said mixture C used in step i ') of the present process can be purified beforehand before being used. In fact, if said mixture C comprises impurities having a boiling point lower than the boiling point of 2,3,3,3tetrafluoro-1-propene and optionally heavy impurities, the present process can comprise prior to step i ') the steps:

i- 1 ¹ ) use of a composition comprising 2,3,3,3-tetrafluoro-1-propene, impurities having a boiling point lower than the boiling point of 2,3,3,3tetrafluoro- l-propene, HF, 1,1,1,2,2-pentafluoropropane (245cb), and trans-1,3,3,3tetrafluoro-l-propene (1234ze-E), optionally or not, at least one of the selected compounds among the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans1.2.3.3.3- pentafluoropropene (1225ye-E), cis-1,2,3,3,3-pentafluoropropene (1225ye-Z),

3.3.3- trifluoropropene (1243zf), and optionally or not heavy impurities;

ii- Γ) distillation of said composition from step i-1 ') to remove impurities having a boiling point below the boiling point of 2,3,3,3tetrafluoro-1-propene at the top of the column and form a first stream comprising 2,3,3,3-tetrafluoro-lpropene, HF, 1,1,1,2,2-pentafluoropropane (245cb), and trans-1,3,3,3-tetrafluoro-lpropene (1234ze -E), optionally or not at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2tetrafluoroethane (134a), chloropentafluoroethane (115), trans- 1,2,3,3,3pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,33064629 trifluoropropene (1243zf), and optionally or not impurities heavy, recovered at the bottom of the distillation column;

iii-Γ) optionally or not, distillation of said first stream recovered at the bottom of the distillation column in step ii-Γ) to recover a second stream comprising 2,3,3,3-tetrafluoro-1 at the top of the column propene, 1,1,1,2,2-pentafluoropropane (245cb), HF and trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), optionally or not at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-l, 2,3,3,3-pentafluoropropene ( 1225ye-E), cis1,2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf), and at the bottom of the distillation column a stream comprising the heavy impurities;

said first stream recovered in step ii-Γ) or said second stream recovered in step iii-1 ') correspond to said mixture C implemented in step i').

According to a second aspect, the present invention provides a method for producing the

2,3,3,3-tetrafluoro-1-propene. In addition, this process can include its purification. Thus, the present invention provides a process for the production of 2,3,3,3-tetrafluoro-l-propene comprising the steps of:

A) fluorination in the presence of a catalyst of a compound of formula CH ( _n +2) (X) _m CH _p (X) (n + i) -CX (3 + pm) where X independently represents F or Cl; n, m, p are independently of each other 0 or 1 with (n + m) = 0 or 1, (n + p) = 0 or 1 and (mp) = 0 or 1, at least one X being Cl;

B) recovery of a stream comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2pentafluoropropane (245cb), HF, trans-l, 3,3,3-tetrafluoro- l-propene (1234ze-E), and optionally or not at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a) , chloropentafluoroethane (115), trans-1,2,3,3,3-pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3- trifluoropropene (1243zf);

C) implementation of the process for purifying 2,3,3,3-tetrafluoro-1-propene according to the present invention from the stream recovered in step B).

According to a preferred embodiment, the current recovered in step B) corresponds to said mixture C according to the present invention.

Preferably, the stream comprising said organic extractant can be recycled in step a). Preferably, the stream comprising trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E) and optionally or not at least one of the compounds selected from the group consisting of chloromethane (40), 1,1- difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3, 3,3pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf) can be purified or destroyed by incineration.

According to a particular embodiment, the stream recovered in step B) of the process for producing 2,3,3,3-tetrafluoro-1-propene can comprise impurities having a boiling point lower than the boiling point 2,3,3,3-tetrafluoro-1-propene. In this case, prior to step C), the stream recovered in step B) can undergo a prior distillation ΒΓ) to remove at the top of the distillation column said impurities having a boiling point below the boiling point 2,3,3,3-tetrafluoro-l-propene and form a first stream comprising 2,3,3,3-tetrafluoro-l-propene, HF, 1,1,1,2,2-pentafluoropropane, trans- 1,3,3,3-tetrafluoro-l-propene (1234ze-E) and optionally or not at least one of the compounds chosen from the group consisting of chloromethane (40), 1,1-difluoroethane (152a),

1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye -Z), 3,3,3trifluoropropene (1243zf), recovered at the bottom of the distillation column. This latter stream recovered at the bottom of the distillation column is then subjected to step C) of the process for producing 2,3,3,3-tetrafluoro-1-propene, and corresponds to said mixture C.

According to a particular embodiment, the stream recovered in step B) of the process for producing 2,3,3,3-tetrafluoro-1-propene can comprise heavy impurities. In this case, prior to step C), the stream recovered in step B) can undergo a prior distillation B2 ′), subsequent or not in step ΒΓ), to remove said impurities at the bottom of the distillation column. heavy; and form a first stream comprising 2,3,3,3-tetrafluoro-lpropene, 1,1,1,2,2-pentafluoropropane, HF, trans-1,3,3,3-tetrafluoro-l-propene (1234ze- E) and optionally or not at least one of the compounds chosen from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans -1,2,3,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3,3pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf), recovered at the head of distillation column. This latter stream recovered at the top of the distillation column is then subjected to step C) of the process for producing 2,3,3,3-tetrafluoro-1-propene and corresponds to said mixture C.

According to a particular embodiment, the stream recovered in step B) of the process for producing 2,3,3,3-tetrafluoro-1-propene can also comprise HCl. The hydrochloric acid can be recovered by distillation before or after step ΒΓ independently of the other steps of the process.

More particularly, step A) is carried out from 1,1,2,3-tetrachloropropene, 2,3,3,3, -tetrachloropropene, 1,1,1,2,3-pentachloropropane, 2-chloro- 3,3,3-trifluoropropene,

1.2- dichloro-3,3,3-trifluoropropane, 2-chloro-l, l, l, 2-tetrafluoropropane, 1,1,1,2,2pentafluoropropane and 1,1,1,2,2-pentachloropropane, preferably from 1,1,1,2,3pentachloropropane, 1,1,2,3-tetrachloropropene, 2,3,3,3-tetrachloropropene, 2-chloro-3,3,3trifluoropropene, 2-chloro-l, l , l, 2-tetrafluoropropane, l, 2-dichloro-3,3,3-trifluoropropane,

1.1.1.2.2- pentafluoropropane and 1,1,1,2,2-pentachloropropane or a mixture of these in particular from 1,1,1,2,3-pentachloropropane (240db).

The catalyst used in the present process for producing 2,3,3,3tetrafluoropropene can for example be based on a metal comprising a transition metal oxide or a derivative or a halide or an oxyhalide of such a metal. Mention may be made, for example, of FeCb, chromium oxyfluoride, chromium oxides (possibly subjected to fluorination treatments), chromium fluorides and their mixtures. Other possible catalysts are catalysts supported on carbon, antimony-based catalysts, aluminum-based catalysts (e.g. AIF3 and Al2O3, alumina oxyfluoride and alumina fluoride).

It is generally possible to use a chromium oxyfluoride, a fluoride or an aluminum oxyfluoride, or a supported or unsupported catalyst containing a metal such as Cr, Ni, Fe, Zn, Ti, V, Zr, Mo, Ge, Sn, Pb, Mg, Sb.

Reference may be made in this regard to document WO 2007/079431 (in p.7,1.1-5 and 2832), in document EP 939071 (paragraph [0022]), in document WO 2008/054781 (in p.9 1.22p .101.34), and WO 2008/040969 (claim 1), to which express reference is made.

The catalyst is more particularly preferably based on chromium and it is more particularly a mixed catalyst comprising chromium.

According to one embodiment, a mixed catalyst comprising chromium and nickel is used. The Cr / Ni molar ratio (based on the metallic element) is generally

0.5 to 5, for example 0.7 to 2, for example about 1. The catalyst can contain from 0.5 to 20% by weight of nickel.

The metal may be present in metallic form or in the form of a derivative, for example an oxide, halide or oxyhalide. These derivatives are preferably obtained by activation of the catalytic metal.

The support is preferably made with aluminum, for example alumina, activated alumina or aluminum derivatives, such as aluminum halides and aluminum oxyhalides, for example described in the document US 4,902,838, or obtained by the activation process described above.

The catalyst may comprise chromium and nickel in an activated or inactive form, on a support which has been subjected to activation or not.

Reference may be made to document WO 2009/118628 (in particular on p.4, l.30-p.7 1.16), to which express reference is made here.

Another preferred embodiment is based on a mixed catalyst containing chromium and at least one element chosen from Mg and Zn. The atomic ratio of Mg or Zn / Cr is preferably from 0.01 to 5.

Before its use, the catalyst is preferably subjected to activation with air, oxygen or chlorine and / or with HF.

For example, the catalyst is preferably subjected to activation with air or oxygen and HF at a temperature of 100 to 500 ° C, preferably from 250 to 500 ° C and more particularly from 300 to 400 ° C. The activation time is preferably from 1 to 200 h and more particularly from 1 to 50 h.

This activation can be followed by a final fluorination activation step in the presence of an oxidizing agent, HF and organic compounds.

The molar ratio HF / organic compounds is preferably from 2 to 40 and the molar ratio oxidizing agent / organic compounds is preferably from 0.04 to 25. The temperature of the final activation is preferably from 300 to 400 ° C and its duration preferably from 6 to 100 h.

The gas phase fluorination reaction can be carried out:

- with an HF / compound molar ratio of formula (I) and / or (II) of 3: 1 to 150: 1, preferably from 4: 1 to 125: 1 and more particularly preferably from 5: 1 to 100 : 1;

- with a contact time of 3 to 100 s, preferably 4 to 75 s and more particularly 5 to 50 s (volume of catalyst divided by the total incoming flow, adjusted to the operating temperature and pressure);

- At a pressure ranging from atmospheric pressure to 20 bara, preferably from 2 to 18 bara and more particularly from 3 to 15 bara;

- At a temperature (catalyst bed temperature) of 200 to 450 ° C, preferably from 250 to 400 ° C, and more particularly from 280 to 380 ° C.

The duration of the reaction step is typically from 10 to 8000 hours, preferably from 50 to 5000 hours and more particularly from 70 to 1000 hours.

An oxidizing agent, preferably oxygen, can optionally be added during the fluorination reaction. The oxygen / organic compound molar ratio can be from 0.005 to 2, preferably from 0.01 to 1.5. Oxygen can be introduced pure or in the form of air or an oxygen / nitrogen mixture. You can also replace oxygen with chlorine.

Fig. 1 schematically illustrates a device implementing a process for producing 2,3,3,3-tetrafluoropropene according to a particular embodiment of the present invention. Hydrofluoric acid 1 is brought into contact with 1,1,1,2,3pentachloropropane (240db) 2 in a reactor 3. Reactor 3 can also be supplied with stream 10 comprising 1,1,1,2,2 -pentafluoropropane (245cb) and from the recycling of the purification process of 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2-pentafluoropropane (245cb). The mixture obtained and comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2pentafluoropropane (245cb), HF, trans-l, 3,3,3-tetrafluoro-l-propene ( 1234ze-E) and optionally at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans -1,2,3,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3,3pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf), is recovered at the outlet of reactor and conveyed to a distillation column 5 via line 4. The mixture may also comprise HCl and heavy impurities or having a boiling point lower than that of

2,3,3,3-tetrafluoro-1-propene. The stream obtained at the bottom of the distillation column comprises part of the HF and optionally heavy impurities conveyed to the purification device 7 via the conduit 6 to purify HF which will be optionally recycled in 3. The mixture conveyed via the conduit 8 to a device 9 purification includes 2,3,3,3-tetrafluoro-lpropene, 1,1,1,2,2-pentafluoropropane (245cb), HF, trans-l, 3,3,3-tetrafluoro-l-propene (1234ze -E) and optionally at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans- 1,2,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3,33064629 pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf); and corresponds to said mixture C according to the present invention.

FIG. 2a represents a simplified diagram of a part of the device 9 implementing a process for the purification of 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2pentafluoropropane according to a mode of particular embodiment of the invention. In particular, FIG. 2a schematically represents the stages of recovery of hydrofluoric acid as described in stages i ') to v') according to the present invention. The mixture C comes from the pipe 8 described in FIG. 1. The mixture C feeds a device 12 in which it is brought into contact with a hydrofluoric acid solution 11 ′ or a hydrofluoric acid solution coming from the device 14 via the line 30 having a concentration varying between 65 and 75% by weight. The device 12 can be, for example, a hydro-scrubber. The contact between the hydrofluoric acid solution 11 'or a hydrofluoric acid solution from the device 14 via the line 30 and the mixture C generates the formation of a two-phase current which is conveyed to a storage device 14 by the pipe 23. The storage device 14 makes it possible to separate the two-phase current into a gas phase and a liquid phase. The gaseous phase of said two-phase current is conveyed through line 24 to the absorption column 13 comprising 3 absorption stages 31a, 31b and 31c. The absorption column 13 is also supplied by an aqueous flow 17. In this embodiment, the aqueous flow 17 supplies the absorption column 13 at the top of the absorption column 17, that is to say above the three absorption stages 31a-31c. Alternatively, the aqueous stream 17 can feed the absorption column 13 above each of the absorption stages 31a-31c. A gas stream C1 as described in the present application can be extracted at the top of the absorption column 17 via line 26 to supply a neutralization device 15. In addition, at the bottom of the absorption column 17, an aqueous solution d hydrofluoric acid corresponding to said stream C2 is recycled to the storage device 14 via line 25. The stream C1 is neutralized in the neutralization device 15 by an alkaline solution of NaOH at 20%. The alkaline solution 18 feeds the neutralization device 15 via the line 29. The neutralized current is evacuated through the line 2J and recovered in 20 to be dried over a molecular sieve of 3A. The neutralized and dried current corresponds to current C4 according to the present process. This can therefore be compressed and liquefied at a pressure of at most 8 bara (current C5 according to the present process). A spent alkaline solution 19 can be extracted from the neutralization device 15 to be either recycled via lines 28 and 29 or discharged via line 28 for further treatment. The liquid phase resulting from the mixture of the liquid phase of the two-phase stream and of the stream C2 stored in the storage device 14 is conveyed to a distillation column 16 via the pump 32 and the pipe 33 to form the stream D recovered at the head of the column distillation 21 and the current E recovered at the bottom of the distillation column 22. The pump 32 also supplies the liquid phase resulting from the mixing of the liquid phase of the two-phase current and of the current C2 stored in the storage device 14 to the device 12 via the pipe 30. The pump 32 is thus configured to allow the supply of the distillation column 16 and the device 12 alternately or simultaneously, preferably simultaneously.

The mixture C can be purified before its use according to the present process. This is described in FIGS. 2b and 2c according to particular embodiments. A mixture including

2,3,3,3-tetrafluoro-l-propene, HF, 1,1,1,2,2-pentafluoropropane (245cb), trans-1,3,3,3tetrafluoro-l-propene (1234ze-E) and impurities having a boiling point lower than the boiling point of 2,3,3,3-tetrafluoro-1-propene is supplied at 41. The mixture is transferred to a distillation column 42 via line 43. The impurities having a boiling point lower than the boiling point of 2,3,3,3-tetrafluoro-l-propene are recovered at the top of the distillation column 42 and conveyed via line 45 to an incinerator or a purification device 50. The mixture C is obtained at the bottom of the distillation column and is conveyed to the device 12 described in FIG. 2a via line 44. In another particular embodiment illustrated in FIG. 2c, the mixture also includes heavy impurities. In this case, a distillation can be carried out from the stream obtained at the bottom of the distillation column 42. The latter is therefore conveyed by line 44 to the distillation column 46. The heavy impurities are recovered at the bottom of the distillation column 47. The current recovered at the head of the distillation column 46 corresponds to said mixture C. This current is transferred via the conduit 48 to the device 12 to be treated there as explained above in relation to FIG. 2a.

According to the particular embodiment of the invention, the current C1, C3, C4 or C5 corresponds to said first composition according to the present invention which is treated by extractive distillation as illustrated in FIG. 2d. The extractive distillation carried out in 66 aims at separating 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2-pentafluoropropane (245cb) from the other constituents of the mixture. The extractive distillation column 66 is supplied with the organic extraction agent 70. The stream comprising 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2pentafluoropropane (245cb) is recovered at the head of the distillation column 66 and conveyed to the distillation column 72 via the conduit 67. The organic extraction agent 70 and the trans3064629

1.3.3.3- tetrafluoro-1-propene (1234ze-E) are recovered at the bottom of the distillation column 66 to be conveyed to the distillation column 69 where these are separated. The organic extraction agent is recovered at the bottom of the distillation column 69 in order to be recycled to the extractive distillation column 66 via the conduit 71. The trans-1,3,3,3-tetrafluoro-1-propene is recovered in distillation column head 69 to be conveyed to an incinerator or a purification device 50. The distillation column 72 allows the separation between the

2.3.3.3- tetrafluoro-l-propene recovered at the top of distillation column 73 and 1,1,1,2,2pentafluoropropane recovered at the bottom of distillation column 74. 1,1,1,2,2pentafluoropropane can be recycled in the reactor 3 described in FIG. 1 above.

The current Cl, C3, C4 or C5 can also comprise at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a),

1.1.1.2- tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3trifluoropropene (1243zf). These compounds are found in the same current as trans1.3.3.3- tetrafluoro-l-propene (1234ze-E). They are therefore absorbed by the organic extraction agent during the extractive distillation 66 to be conveyed to the distillation column 69 where they are recovered at the top of the distillation column with the trans-1,3,3,3-tetrafluoro -lpropene (1234ze-E) and are incinerated or purified in 50.

Method of selecting the organic extractant

The selection of the organic extraction agent is determined by the use of the CosmoRS model implemented in the COSMOTHERM software. For this selected binary couple, a separation factor is calculated for each of the solvents studied by the following equation:

If, 2 = (7i, s * P1) / (y2, s * P2) in which yi, s represents the activity coefficient of the first compound 1 in the organic extraction agent considered at infinite dilution,

PI represents the saturated vapor pressure of the first compound 1, / 2, s represents the activity coefficient of the second compound 2 of the binary couple in the organic extraction agent considered at infinite dilution,

P2 represents the saturation vapor pressure of the second compound.

An absorption capacity is also calculated for each of the solvents studied and for a binary couple (1,2) considered. The absorption capacity is calculated by the formula C2, s = 1 / (/ 2, s) in which / 2, s represents the activity coefficient of the second compound of the binary couple considered in said organic extracting agent studied at infinite dilution.

The calculations are repeated for each organic extractant studied. Minimum values of separation factor and absorption capacity are identified in order to allow sufficient separation between the first compound and the second compound of the binary pair (1,2) considered. The saturated vapor pressure is considered for a temperature of 25 ° C.

Examples

To purify 2,3,3,3-tetrafluoro-l-propene, the binary couple 2,3,3,3-tetrafluoro-l-propene / trans-l, 3,3,3-tetrafluoro-l-propene ( 1234ze-E) is considered to select the organic extractant (see Table 1). The mixture to be purified includes 2,3,3,3-tetrafluoro-lpropene, 1,1,1,2,2-pentafluoropropane, and trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E) .

Table 1 - Capacity and separation factor of the organic extractant

Extraction agent organic Capacity absorption (1234zeE) Factor separation (1234yf / 1234zeE) Factor separation (245cb / 1234zeE) Ethylamine 1.95 2.92 3.60 Isopropylamine 1.85 2.56 3.14 Diethylether 1.48 1.79 1.68 n-propylamine 1.86 2.61 3.14 Diethylamine 1.57 1.88 2.18 Diethoxymethane 1.41 1.86 1.63 Isopropylacetate 1.42 2.15 1.79 3-pentylamine 1.63 2.05 2.39 2-methoxyethanamine 1.98 3.19 3.80 tert-butylacetate 1.37 2.10 1.63 1,4-dioxane 1.09 2.24 1.92 1,1-diethoxyethane 1.54 1.90 1.78 trimethoxymethane 1.28 2.11 1.81 n-pentylamine 1.64 2.31 2.71

1,3-dioxane 1.09 2.23 1.93 sec-butylacetate 1.45 2.12 1.79 1,2-diaminoethane 1.29 4.43 6.88 l-methoxy-2-propanol 0.87 2.31 2.15 1,2-propanediamine 1.50 3.54 4.92 n-butylacetate 1.35 2.14 1.86 2-methoxy-l-propanol 0.87 2.31 2.13 hexanal 1.09 1.98 1.72

Claims (12)

Claims 1. Process for the purification of 2,3,3,3-tetrafluoro-l-propene (1234yf) from a first composition comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1 , 2,2-pentafluoropropane (245cb) and trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E), said method comprising the steps of: a) bringing said first composition into contact with at least one organic extracting agent to form a second composition; b) extractive distillation of said second composition to form: i) a third composition comprising said organic extractant and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E); and ii) a current comprising 2,3,3,3-tetrafluoro-1-propene (1234yf) and the 1,1,1,2,2-pentafluoropropane (245cb), c) recovering and separating said third composition to form a stream comprising said organic extractant and a stream comprising trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E); preferably the stream comprising said organic extractant is recycled to step a); characterized in that the first composition is obtained from a mixture C comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans-l, 3,3,3-tetrafluoro1-propene (1234ze-E) and HF, said mixture being subjected to the following stages: i ') bringing said mixture C into contact with an aqueous solution of hydrofluoric acid of concentration greater than 40% by weight to form a two-phase current comprising 2.3.3.3- tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans-l, 3,3,3-tetrafluoro1-propene (1234ze-E) and HF, ii ') storage of said second two-phase current in a buffer tank, said two-phase current consisting of a liquid phase and a gas phase, iii ') passage of said gaseous phase from said second two-phase current in an absorption column fed against the current by an aqueous stream to form a current Cl comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans1.3.3.3- tetrafluoro-l-propene ( 1234ze-E) and a current C2 including HF. 2. Method according to claim 1 characterized in that it comprises the steps: iv ') neutralization of said current C1 obtained in step iii') with an alkaline aqueous solution to form a neutralized current C3, and ν ') drying of said neutralized current C3 obtained in step iv') on molecular sieve to form a neutralized and dried stream C4 comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2pentafluoropropane (245cb), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze -E). 3. Method according to any one of the preceding claims, characterized in that the aqueous hydrofluoric acid solution used in step i ') is at a temperature between 0 to 30 ° C before it is brought into contact with said mixture C . 4. Method according to any one of the preceding claims, characterized in that the liquid phase resulting from the mixing of said liquid phase of said second two-phase stream and of said stream C2 is distilled to form a stream D, preferably at the top of the distillation column, comprising hydrofluoric acid containing less than 500 ppm of water and a stream E, preferably at the bottom of the distillation column, comprising hydrofluoric acid in the form of an aqueous solution of concentration less than 50% by weight. 5. Method according to any one of the preceding claims, characterized in that the ratio between the flow rate of the aqueous flow expressed in kg / h feeding the absorption column in step iii ') and the quantity of hydrofluoric acid in said mixture C expressed in kg / h is between 0.05 and 1.22, preferably between 0.33 and 0.54. 6. Method according to any one of the preceding claims, characterized in that it also comprises a step of recovering said stream ii) comprising 2,3,3,3tetrafluoro-l-propene and 1,1,1,2, 2-pentafluoropropane (245cb) obtained in step b), and of distillation thereof to form a stream A comprising 2,3,3,3-tetrafluoro-1-propene and a stream B comprising 1,1,1 , 2,2-pentafluoropropane (245cb). 7. Method according to any one of the preceding claims, characterized in that said first composition also comprises at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1 , 2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), cis1,2,3,3,3-pentafluoropropene (1225ye-Z), 3 , 3,3-trifluoropropene (1243zf). 8. Method according to any one of the preceding claims, characterized in that said organic extraction agent has a separation factor Si, 2 greater than or equal to 1.1, said separation factor being calculated by the formula Si, 2 = (yi, s * Pl) / (y2, s * P2) in which yi, s represents the activity coefficient of 2,3,3,3-tetrafluoro-l-propene in said organic extraction agent with infinite dilution , Pl represents the saturation vapor pressure of 2,3,3,3-tetrafluoro-l-propene, y2, s represents the activity coefficient of trans-l, 3,3,3-tetrafluoro-l-propene (1234zeE) in said organic extraction agent with infinite dilution, P2 represents the saturated vapor pressure of trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E); advantageously, the separation factor is greater than or equal to 1.2, preferably greater than or equal to 1.4, more preferably greater than or equal to 1.6, in particular greater than or equal to 1.8, more particularly greater than or equal at 2.0. 9. Method according to any one of the preceding claims, characterized in that said organic extraction agent has a separation factor Si, 2 greater than or equal to 1.1, said separation factor being calculated by the formula Si, 2 = (yi, s * Pl) / (y2, s * P2) in which yi, s represents the activity coefficient of 1,1,1,2,2-pentafluoropropane (245cb) in said organic diluting agent infinite, Pl represents the saturated vapor pressure of 1,1,1,2,2-pentafluoropropane (245cb), y2, s represents the activity coefficient of trans-l, 3,3,3-tetrafluoro-l-propene (1234zeE ) in said organic extraction agent with infinite dilution, P2 represents the saturated vapor pressure of trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E); advantageously, the separation factor is greater than or equal to 1.2, preferably greater than or equal to 1.4, more preferably greater than or equal to 1.6, in particular greater than or equal to 1.8, more particularly greater than or equal at 2.0. 10. Method according to any one of the preceding claims, characterized in that said organic extraction agent has an absorption capacity C2, s greater than or equal to 0.20, said absorption capacity being calculated by formula C2, s = l / (y2, s) in which y2, s represents the activity coefficient of said at least one of the compounds consisting of trans-1,3,3,3-tetrafluoro-lpropene (1234ze-E) in said agent organic extraction at infinite dilution, preferably y2, s represents the activity coefficient of said at least one of the compounds consisting of trans-1,3,3,3tetrafluoro-l-propene (1234ze-E), in said agent organic extraction with infinite dilution; advantageously, the absorption capacity C2, s is greater than or equal to 0.40, preferably greater than or equal to 0.60, more preferably greater than or equal to 0.80, in particular greater than or equal to 1.0. 11. Method according to any one of the preceding claims, characterized in that said organic extraction agent is chosen from the group consisting of ethylamine, isopropylamine, diethylether, n-propylamine, diethylamine, propanone, methylacetate, butanone, diethoxymethane, isopropylacetate, 3-pentylamine, 2-methoxyethanamine, tertbutylacetate, 1,4-dioxane, 1,1-diethoxyethane, trimethoxymethane, n-pentylamine, 1,3dioxane, sec-butylacetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1,2-propanediamine, nbutylacetate, 2-methoxy-1-propanol, hexanal. Preferably, said organic extractant is chosen from the group consisting of ethylamine, isopropylamine, diethylether, npropylamine, diethylamine, diethoxymethane, isopropylacetate, 3-pentylamine, 2methoxyethanamine, tert-butylacetate, 1,4-dioxane, 1,1- diethoxyethane, trimethoxymethane, n-pentylamine, 1,3-dioxane, sec-butylacetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1,2propanediamine, n-butylacetate, 2-methoxy-l-propanol, hexanal. 12. Process for the production and purification of 2,3,3,3-tetrafluoro-l-propene comprising the steps of: A) fluorination in the presence of a catalyst of a compound of formula CH ( _n +2) (X) _m CHp (X) (n + i) -CX (3 + pm) where X independently represents F or Cl; n, m, p are independently of each other 0 or 1 with (n + m) = 0 or 1, (n + p) = 0 or 1 and (mp) = 0 or 1, at least one X being Cl; B) recovery of a stream comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2pentafluoropropane (245cb), trans-l, 3,3,3-tetrafluoro-l- propene (1234ze-E), and optionally or not at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene ( 1243zf); C) implementation of the process for purifying 2,3,3,3-tetrafluoro-1-propene according to any one of claims 1 to 11 from the stream recovered in step B). τ — I ώ LL